I've personally seen WAY more abusive and hateful comments on Facebook, from real accounts of real people, with pictures and friends and everything, than I have ever seen on YouTube. This may be very locale dependent, but in my country (Romania, which has a pretty large proportion of people online from very socially conservative backgrounds) you can easily find extremely explicitly misoginistic, racist, homophobic, and just plain hateful comments coming from real FB and Instagram accounts, again, from people using their real names and faces and everything. I've seen far fewer similar comments on YouTube videos, even ones from the same country.