"I'm not a humanist. I'm just not that keen on defining myself by my species, and I'm not going to join a group that willfully excludes squid."

That's really a bad argument. You don't have to like the word "humanist" to be one. Modern humanists are normally not centered around humans, they very well acknowledge that humans are animals too. It very often are the humanists who call for animal rights.

Just the same with "brights". You don't have to like the word to be of the opinion that a naturalist movement that fights for the rights of naturalists on a democratic and voluntary basis is a good idea.

I would even say it is incredibly childish to come up again and again with such ridiculous semantic details, when it's really about something else and far more important.