[Source not online at time of site build.]
Telling someone that they have the freedom to go build their own
instance isn't (necessarily) telling someone to fuck off. (Maybe in
that case it was, I don't know the details.)
There are 4 software freedoms that geeks talk about, the freedom to
use, study, improve, and share your software.
The point is: you could. Start up a Nazi site, start up a community
around knitting. You own it, with all of the maintenance costs that
are implied with ownership, and it seems like a pain in the ass
frankly to run these servers.
But it's up to you. There are no gate keepers.
It will then be your problem, and people can complain that they don't
like your politics.