I think the,
hate, of opposition players, is a product of Professionalism.
While club supporters might get to see them in the clubhouse after games, & when they're coaching the minis, or around with their own families; & generally see them off the pitch; the rest of us just get the 80mins when their being wankers, to the best of their ability.
I know the difference between my, On Pitch persona; & Off; were very much Jekyll, & Hyde. Mates of mine couldn't believe what a bastard I was, when I happened to be on the opposite side; & it was probably just as well we were mates, before I met them on the pitch
Keets Biography was a hot topic before Christmas in Ireland; because they published it to get it in those Christmas stockings. It caused the same response in Ireland, at the time; & it was nice to see such support for him; & gratitude, for him opening up about such a difficult topic, & show young men, in particular; that it's okay to talk about their mental health; & there is help available.