People hated Charlie Kirk primarily because of his aggressive, hateful rhetoric and political positions, especially targeting LGBTQ+ communities, racial and ethnic minorities, and others who disagreed with him. He was known for spreading hate and promoting violent and dehumanizing messages, particularly against transgender people, which many found abhorrent. Kirk also fostered a culture of fear and hostility, including pushing conspiracy-like "professor watchlists" and incendiary statements about various social and political issues. His legacy was marked by a relentless campaign of hate and contempt for human dignity, which made him a highly polarizing and disliked figure by many.
Separately, there is also hate directed toward a different "Kirk," Kirk Hammett, Metallica’s guitarist, but in that context, the criticism tends to be about his music style, perceived uninspired solos, and his attitude toward criticism in the music world—not related to Charlie Kirk. This is a different domain of criticism based on artistic opinion rather than ideological or political reasons.
Therefore, if the question is about "Kirk" in the political context, the hatred mainly stems from Charlie Kirk's harsh anti-LGBTQ+ positions and incendiary, divisive political tactics. If about "Kirk" in music, it relates to artistic and stylistic criticism.