When I taught 9th graders I saw the incipient disrepect for girls frequently. Boys would trot out the "B" word or call other guys out for being "pussies." Their childish concept of being a man was being the most dominant. Some could only find male identity by rejecting everything female. Without dads or male role models, a lot more guys these days are never taught to respect women, so they learn from other dudes, porn, and online spaces where their immature opinions are supported. A lot of these incels are guys who were neglected or rejected by their dads, lack social skills, and/or hate women as symbols of their low social status. I'm not justifying their hatred, but just to say they grow up twisted in a culture (and world) that doesn't respect women, animals, nature. They are one of the many symptoms of an unbalanced social ecosystem. Like a lot of social problems, of course, it's worse in America, where solving problems with violence is common.