It's still valuable for finding people who are arguing in bad faith. Here's another one: make sure that the person you're arguing with about taxes understands how marginal tax rates work.

People feel confident repeating things they've heard often, with a sarcastic smirk, because the ubiquity of the thing they're repeating gives them some security that if they're called on to defend those things, someone more knowledgeable will probably show up and help.

The most depressing and ironic thing is when a self-proclaimed socialist cites the "crowded theater" thing, which was used to jail socialists speaking out against a war.