But in this case, it’s a perfect analogue, that illustrates why decrying censorship here is odd.
Reddit can kick people out if they don’t like the behaviour. This happens every day in businesses all over the world (virtual and non virtual) and it is not decried and for the most part is approved of.
No it's not a perfect analogue. To make the cinema comparison work: There is a cinema. You can rent rooms in that cinema. You and your friends go in to talk about stuff. Someone else comes in and "shushes" you instead of going to another room where nobody is in.
Reddit can also kick out people for having the wrong opinion, as they do, as was observed. Banning for the wrong opinion is of course censorship. Banning for specific lingo used by those people is also censorship.
There is difference between banning for wrong opinions and banning for eg. spamming. The line is slim.