Hullbreacher was a bad card.
In theory, Hullbreacher was a way for blue decks to shut down overpowered value engines that would otherwise end the game. In practice, Hullbreacher was a value engine of its own that could generate incredible card advantage and shut down all of your opponents with a single Wheel of Fortune. The decks that took advantage of this interaction didn't have to wait for an opponent to overextend—they could do all of it themselves for six mana. The table would be left so powerless that, if the Hullbreacher player didn't win immediately, the rest of the players would concede out of boredom.
At any level of play, Commander games are won based on the number of cards you can have access to through drawing, tutoring, or Chord of Calling into play. Drawing cards is such an integral part of the game that players have been complaining for years about how weak White's color identity is because it isn't allowed to draw cards. Magic, at its core, is a game of managing resources, and drawing cards is one of the stronger ways to increase your resources.
For every way to play Commander, there are cards that can disrupt, punish, or even remove that style of play. Graveyards can be exiled, creatures can be wiped, and you can even stop planeswalkers from being able to do anything.
Similarly, there have always been ways to disrupt your opponent's ability to draw cards, but these cards have often been.. underwhelming.
Cards like Nekusar, the Mindrazer and Underworld Dreams have been draining players for years, and can even take advantage of the same wheel effects that made Hullbreacher a terror. If life loss isn't enough to keep your opponents from drawing multiple cards in a turn, Mind's Eye and Consecrated Sphinx can help you keep up or even generate more value than your opponents.
Though these cards work to achieve parity or give you advantage when your opponents draw cards, it wasn't until Notion Thief came along that you could actually punish your opponent for even trying to draw cards. Now you had a card that stopped your opponents from drawing additional cards and gave the advantage to you instead. Since it was playable at instant-speed, Notion Thief could be a hidden bullet kept in hand until your opponent tried to play something like Windfall or Brainstorm.
Further iterations of draw-hate skirted the line between unplayable and ban-worthy. Alms Collector is a creature that can be cast at instant speed like Notion Thief, but only stops an opponent from drawing two or more cards at the same time. Leovold, Emissary of Trest, on the other hand, is a Sultai (blue-black-green) Legendary creature that has similar text to Notion Thief, but can be cast from the command zone and is harder to remove once played. Because he could be played from the command zone repeatedly and remove everyone's hand with a single Wheel effect, Leovold was banned.
In more recent releases, we've seen a few additional ways to impact your opponent's ability to draw cards. Narset, Parter of Veils is a planeswalker with the static ability that keeps opponents from being able to draw more than one card per turn. While Narset is still the target of complaints, a planeswalker with no way to protect itself on board that requires two blue mana to cast is a tough sell in decks that aren't mono-blue.
Smothering Tithe released in the same block as Narset, Parter of Veils, but it's a different beast of draw-hate altogether. This enchantment doesn't stop players from drawing cards, but it generates incredible value if the opponent doesn't pay the tax. Instead of drawing you cards or dealing damage, Smothering Tithe gives you a resource worth its weight in gold: Treasure. A single round with Smothering Tithe has the potential to give you at least 3 Treasure if no one pays the tax, and can push you far ahead of your opponents if they are still struggling to set up.
Smothering Tithe presents a much stronger threat than any previous draw-hate card, but it doesn't take away a player's ability to draw cards, so your opponents have time to find an answer before your Treasure tokens let you take over the game.
Then came Hullbreacher.
Hullbreacher took the best parts of each previous version of draw-hate and combined them into one card. It has the flash keyword so it can stay in your hand until the moment when someone goes to draw a bunch of cards. It's less mana-intensive than Notion Thief and Narset, Parter of Veils, so it's easier to slot into decks, and you only needs three mana open to cast it. Hullbreacher not only stops any draw after the first in a turn, it gives you a Treasure token for each card your opponent tried to draw.
As soon as Hullbreacher was previewed, the Commander community seemed dedicated to breaking the card. Like with other draw-hate cards, the most effective strategy with Hullbreacher was to combine it with your own wheel effect. With Windfall, it leaves every other player with a single card in their hand, and the controller of Hullbreacher can get up to 21 Treasure Tokens to fuel all of the cards they were able to draw.
Rather than acting as an answer to draw strategies, Hullbreacher quickly became its own win condition that required an immediate answer. While powerful, the problem with Hullbreacher wasn't just that it gave its controller a potentially game-winning advantage. The problem was that stole the ability of other players to come back against that advantage.
Hullbreacher removes your opponents' ability to play the game so that only you can play until the game is over. This isn't the only strategy in Commander that operates on limiting your opponents' options, but decks that focus on Stax or mass land destruction have a bad reputation in casual groups, so the average player doesn't encounter them often. Hullbreacher is like a Stax effect without the symmetry. Unlike other resource denial cards, it was so universally good that it became incredibly common in playgroups and, if it wasn't killed on sight, always led to games where only one player had any options.
When the community couldn't regulate themselves away from empowering strategies that kept playgroups from enjoying Commander, the Rules Committee stepped in to ban the card.
With an established playgroup, it can be really easy to have the conversation of, "we want to keep playing with this card, so we are going to unban it for our games." But it is much harder for someone to walk into an LGS and say, "this card makes for a poor experience for me, can we not play it?" While you may be able to change your play experience with friends, it is a lot tougher to do so when in a new playgroup, so the banlist works to help those players that are just discovering the format or joining a new playgroup. Which is to say, new players.
The Commander banlist, and the Rules Committee and Commander Advisory Group in general, exist to foster the best play experience for the most players possible. If your local meta was able to solve the issue of Hullbreacher before it was banned, congratulations! But for a lot of playgroups and players, this wasn't the case, and Hullbreacher was hurting a lot more games than it was helping.
If you were playing with Hullbreacher and have to take it out of your deck, now you get to add something else to one-up your playgroup (like blazing volley)! Ultimately, if you're reading articles about MTG cards, the Hullbreacher ban wasn't about or for you. It was for the new player that just sleeved up their first Commander deck heading down to their LGS who deserves to have fun just as much as everyone else.
And I'm glad they won't have to deal with Hullbreacher.