Broly is hated by a sizable number of Dragon Ball fans. The villain, who is known as the Legendary Super Saiyan, is one of Goku’s most powerful enemies of all-time. He’s also the only character to serve as the main antagonist in four movies, three of which being non-canon installments. So far, Broly has strictly been a movie character and has never been involved in any of the shows. Despite what the character's repeat appearances might suggest, Broly is not just a popular villain — instead, he may be the franchise's most controversial character.
Broly debuted in the movie, Dragon Ball Z: Broly — The Legendary Super Saiyan as a timid Saiyan warrior controlled by his domineering father. After arriving on Earth, Broly went on an uncontrollable rampage against the Z-Warriors, but was eventually brought down by Goku, who had to rely on energy from his allies. Broly returned in a sequel, Broly – Second Coming, and appeared again in Bio-Broly, where he went up against Gohan, Goten, Trunks, Android 18, and Krillin. Over 20 years later, Broly made his first in-canon appearance in Dragon Ball Super: Broly, which reimagined him with a reworked design and backstory. In the movie, he was utilized as a pawn by Frieza in a scheme to take down Goku and Vegeta.
Despite being the most popular Dragon Ball Z movie villain, Broly has a bit of a polarizing reputation. Though he gets a lot of love from the fandom, he also gets a fair amount of hate. Broly has long been a controversial villain in the Dragon Ball franchise, due in large part to the premise of his character and his relationship with Goku. In the original movies, Broly’s hatred of Goku stems from their days as infants. In the delivery chamber, Broly became frustrated from listening to Goku’s crying. Subconsciously, Broly developed a hatred for him that manifested itself when they met again as adults. Many have felt that this is a poor justification for Broly’s intense hatred for Goku.
In general, Broly is a cool character concept that failed in execution. Since his animosity toward Goku is the primary reason for the Z-Warriors’ conflict with Broly in the Dragon Ball Z movies, his primary motivation needs to make sense in order for fans to understand his character; since the backstory is flat, the character suffers. Another reason why Broly is disliked is his off-the-charts power level — another flaw in his characterization. The immense power isn’t given a proper explanation other than the statement that he’s “the Legendary Super Saiyan.” Finally, there’s also the fact that Broly doesn’t have much to offer personality-wise. As a villain who spends most of his screen time in an enraged state, Broly only utters a few short sentences, and most revolve around his desire to kill Goku.
Some of these problems with Broly were addressed and fixed in the Dragon Ball Super movie. The movie made Broly into a sympathetic character, took away his issues with Goku, and even set up him as a potential hero. But regardless of everything that was changed, it kept the most important aspect of his character, which is his status as a Legendary Super Saiyan who can’t control himself in battle. As a result, a large section of the fanbase who was displeased with the non-canon Broly found the new version to be a much-needed improvement.