That's the thing, it's still an opinion, and it's one with as much validity as the believe that the son of god was conceived by an angel and dies on a cross as far as I'm concerned.

But it's also been accused of indoctrination, has a tendency to sue people for saying anything at all negative about them, former members have reported horror stories about brainwashing, and ultimately the whole thing is based on a book by a pretty poor science fiction author (SRSLY, really really poor).

That and the numerous attempts to hijack websites and or get them shut down, freedom of speech online only works if your host doesn't get bought out from under you and your content removed for "copyright infringement" and similar.

But ultimately? For a lot of the protesters, fun day out meeting like minded loons and taking the piss out of a bunch of nutbags. Why not?