You can be right wing in FOSS networks.

There's two things you can't do (at least if you want to keep a community healthy):

1. Break the rules of the network (which are usually things like: don't spam, don't scam, "Wheaton's Law", etc...).
2. Be so unpleasant to be around that others don't want to be around you.

There are cases of those who dehumanise others (e.g. racists, anti-trans, literal nazis, etc...) who get banned because they're doing the two things you can't do. But in those cases they're not banned because they're right wing, they're banned because those actions break communities, so the community has to ban them to continue existing.