Personally, I would have not pushed this issue, your son would have been worse off with this roommate, IMO.
I doubt that this is true. There are probably other hate-mongering preachers that you/your son just have not noticed.
Again, a blanket statement. While frats do tend to be more conservative, and some may be less tolerant, I know several out gay frat brothers at Penn.
Not to say that being a LGBTQ youth anywhere is going to be peaches and cream - it’s not. Kids are making the transition into adulthood and many, if not most, kids (even if they did not appear so outwardly) struggled to fit in in HS, whether due to gender identity, color, height, SES status, etc. In college, there is less of that, but remnants exist. Being “out” is less traumatic and has fewer “issues” than a generation ago, or even 5 years ago, but one will still encounter pockets of discrimination.