It surely seems like it but I feel like there must be some more effective angle. A common technique is to only let them talk by asking questions which at some point lead to some contradiction which should make them think. It just feels I haven't gotten good enough at it yet.

Me too but sometimes, you just can't help but get your hopes up high that "this time is going to be different". But time is definitely spent better writing longer, thought-provoking posts than replying in some random thread to some random dude. It has more reach and is more convincing. I try to write longer posts to balance stuff like this and this out.