Don't you think that, in many cases, being or acting "macho" is just a pose to hide insecurities about a person's masculinity? It's an overcompensation for their secret feelings of weakness. Most likely, they were brought up in a circumstance where boys are mocked for any display of sensitivity, so they grow up trying to prove how "macho" they are by driving big, loud trucks and shooting guns and shouting disdain and hatred for queer and trans folk.

Then again, some of them might actually be repressing their own same-sex or trans attraction. If they looked at queer and trans folks as flesh and blood humans would run the risk of them getting sexually aroused or, worse yet, feeling affection.