[Bender]

First off, he wasn't a troll. He was simply a guy that disliked MLP. You have to respect that. A troll is someone that cleverly makes someone angry for the fun of it.
This man just happened to make you angry because he insulted you with opinions that do make sense. A troll does it senselessly.

However, his insults should not be justified. You're not in the wrong here, and neither is he. This is just simply two opinions clashing.

Also, I don't mean to offend, but I don't think you "crushed" him. I don't think what you said affected him at all, thus he wasn't "crushed". In fact, it gave him more reason to dislike you further; the harder you fight back, the harder someone will hate you, out of spite.

What I recommend you do is the following when someone insults you.
1) Do not take it personally.
It's either a senseless insult or a personal opinion. It doesn't affect you or your opinion and therefore you should just let it go. I know it's hard to, but it's the best thing you can do.
2) Be nice and logical as possible.
You'll be surprised how being nice can get you out of a jam.
Reply with such things as:
"I can understand why you're angry."
"Hey, no need for rude comments. Let's be civil."
This will give you a firm standpoint that you're looking for no trouble and you're a good guy. It also sets out the chance for him to step down. If it doesn't work, then you have all the right to tell him off (in a civilized manner) as you have already given him the chance.
3) If all else fails, use sarcasm and exaggeration.
This gives him the idea that you honestly don't give a flying fuck and that his insults don't matter.
Such sarcasm consists of:
"Why are you so mean ;_; I thought we were fwens."
"This man obviously doesn't lift."

This is the internet, try your best to not let any of it affect you, or else they succeed in offending you. Always remember to acknowledge what they're saying too (if it's possible), this leaves you informed and not ignorant to what they're saying.

Hope this helps.