With the primaries upon us---there is no shortage of trolls.
I cannot make anyone stop responding to pointless or nuisance comments. You have to want to restrain yourself, because you understand that the only way to get rid of them is to fail to give them the attention they want. A "troll" is not just someone whose comments you disagree with, or even just a nasty or badly-worded comment. A troll is someone who does not, under any possible set of circumstances, care what you think about him or his comments.
He merely wants attention. Negative attention will do. The more you disagree with him, the more he is able to tell himself that he is persecuted and victimized or the only voice of reason or one of the elite few who has the God's-eye view of the world or whatever his current delusion is...and there's more.