The obvious reaction to anything typically free getting paywalled is vehemence, of course - and that's my thought given Reddit's track record.
Still, if it weren't them, I'm thinking about how this could be done in a classy way. Most people are not willing to engage on topics like politics because there will always be an unending army of trolls arguing in bad faith about them or needlessly engaging in flame wars. If there's some form of friction behind entry, that CAN at least get people to think twice about insulting each other.
Price tags as a form of friction are problematic, of course, in that they "only allow access to the rich". As such, I'd also be open to other ways of making it "difficult" to enter in a way that people could still do with no money. The silliest idea that comes to mind is that people must mail a physical postcard requesting entry (which could then loop back to price tags, since that uses a stamp)