It's not banning arguments, just recognising that twitter ads aren't the best medium for certain arguments.
And so on. That feels like a slippery slope to me.
It only feels like a slippery slope if you make no attempt to think about why Twitter is a bad place for certain kinds of debate, and instead assume that whatever traits make Twitter bad for that generalize to the entire public sphere.
Surely if Twitter has to publish content, it would be reasonable to require The New York Times to publish, and promote, an article from Storm Front. Or require Fox to publish, and promote, actual Climate Science content.
Twitter is not even halting the argument, they’re just refusing to artificially promote it above other content.