Trolling has nothing to do with the topic. Trolling is the way you respond to others.
If you ignore the social niceties, you are trolling.
Things like:
1 if you jump in a conversation without a reason, that is considered a troll.
2 If you respond to every comment, that is a troll.
3 if you are insistent on something yet refuse to stop at the same time, you are a troll
4 if you argue with everyone all the time you are definitely a troll
Disagreement isn't a troll though,. It's the persistence, the refusing to stop those behaviors, that makes a troll a troll.