For a long while, Warrior Cats received all the hate. Everyone seemed to highly dislike them and want to bother them all the time. As the WC popularity rose, the hatred and criticism quickly fell. Nine times out of ten, you'll find that people criticizing a certain character species has probably never played one themselves. It's just how some people are, it can get very stressful, especially if they become more and more aggressive with their hate.
It's incredibly rude and unfair to receive hate because of the character you play, but sometimes, you just can't help it. My best advice, ignore them, or block them. Guaranteed as time passes, they'll end up playing as the very species they criticized and then they'll receive the hate from others and have to go what they put you through. It's an endless chain, really. One person playing a species says something another doesn't like and BAM, they have a hate for the species in general. It's pretty childish if you ask me. It's a shame that some the FeralHeart community would deliberately break a rule to express unnecessary hatred toward a species.
I know it's not the same thing, but it follows similar lines; if someone plays an evil character, and someone doesn't like the way their character acts, then that person immediately holds a grudge against the player of the character, even if they don't have that specific personality in real life. Alternatively, they can also begin to hate on the species being played because of one character's personality. I just don't understand where all this hate comes from, it's completely irrelevant and causes nothing but trouble.
And there you have, my opinion ;D xD
~Nym