Insults are a creative field. It doesn't have to be funny. And always respond in kind. If a respectful person makes an intelligent point that you disagree with, try to respond intelligently. If they insult you or others in some way or accuse you of being "-phobic" or "-cist," you would be doing a great disservice to both yourself and the person you're speaking to by responding in any other way but with hostility.

You really think speaking reason to an unreasonable person is going to make them see the light? You think educating someone who doesn't want to be educated is going to make one lick of difference in how they think or see the world? No, it won't. You're not dealing with reasonable people, so don't waste your time. Don't respect people that don't show you respect to begin with, and don't try to argue intelligently with people who are not intelligent. There's always a line in every interaction, and once a person has crossed it, all bets are off.

Don't engage in bad faith arguments with bad faith characters. Tell them to fuck off and move on with your life. If you want to have fun with it, be creative with how you tell them to fuck off, but make sure the point is made and don't give them one ounce more.