It's rooted in misogyny and connected to white supremacy. The existence of LGBTQ+ people shows there are more categories than cishit, which goes against men being the head of the family with the wife being accountable for domestic responsibilities. Non-white societies often had no issues with LGBTQ+ people, or even venerated certain types of queerness. When white people came to colonize, they started by undermining religions and social norms. That meant demonizing anything outside of patriarchal heternormativity. This was further enforced due to how lineage works. Everything passes down from father to oldest son.

Fast forward to today and most of this shit is still in place. Queerness delegitimizes the power structure reactionaries cling to. Reactionaries may or may not be aware this is what they're trying to accomplish. It has become so ingrained within their psyche they lash out as a natural reflex. It is exactly as you say: "Me macho tough guy! Me crush puny weaklings threatening the hierarchy!"