I have been sort of lucky in that I haven't really had online hate and I have only had a couple of instances involving people being inappropriate. However even I know how badly online hate can hurt someone and I don't understand why people feel the need to be mean. They say they are "only telling the truthful" or that they "have the right to their own opinion". Both of those things are valid but they don't give you the right to hurt someone else. There is a difference between being mean and telling the truth. Sometimes the truth doesn't need to be said. You don't like their hair, so what it's their hair not yours!
If something can be changed quickly (in five minutes) then tell them. If there's food in their teeth or something stuck in their hair help them with it, don't mock them. I think sometimes we get too into our own lives that we forget about kindness.
People find it very easy to be mean online as they can't see the victim, they can't see what effect it has on them. They can be completely anonymous. But it hurts them. It hurts to be told you are not good enough, to be mocked for something you can't change. People get violent online as they feel like there are no consequences. Online hate, cyberbullying, mean comments: they all hurt. They hurt a lot. I don't know if this is correct its just something I believe but I think the reason anonymous hate hurts so much is because you don't read it in the attackers voice, you read it in your own.
Please don't be mean to people. As Selena would say "kill them with kindness"