"If you don't like what I have to say, don't comment."
"Positive/friendly comments only, please! "
How that should work:
1.If you don't want certain people to read what you say, get a private account somewhere (like Facebook or some such) where you can control who can see what you post.
2.If you don't like someone's comments, ignore them.
3.If you're going to be negative on someone's post, don't immediately resort to personal attacks against them.For further guidance on being negative while not just being a bully, see the majority of comments by Cynic.
Yeah, I know it's not going to work this way, but what does it hurt to share an opinion?