I know, it’s a platitude, but there it is. If your anger is interpreted as the troll’s effectiveness by the troll… If any attention is positively experienced by the troll…then if your goal is to discuss the topic, ignoring the troll is the best move.
Trolls may not know they are trolls. This can contribute to their seeming, potentially, a couple of posts away from realizing you have a point about them.
Trolls may have certain positive qualities. The most effective trolls must have these.
I think ‘feeding the troll’ is an exceptionally good metaphor. And one is literally feeding the troll oneself: one’s time, one’s effort to explain, one’s energy…
It may look like a discussion, but it’s not. I suspect that trolls are empty and this is a kind of emotional feeding. There is nothing that really engages them in life so they can only enjoy trying to hurt others - however differently they frame what they are doing to themselves, perhaps even thinking they are doing something noble and deeply insightful.
But, really, what difference does it make?
If your goal is to discuss the topic, ignore them. If your goal is to get the troll to have an insight about themselves, good luck.