My first instinct is that sometimes less information is more. I like the fact that our users are essentially anonymous and we don't really have a set identity as a server, aside from being vaguely Canadian/North American. I feel that anyone can be a part of this server and not worry about fitting into the demographic composition or anything else. Sh.itjust.works, it doesn't matter who you are or why you are here, as long as you treat others with respect.
Also, I am a bit wary about the reliability of an online census in general. It seems fairly likely that we will get a lot of junk data mixed in with the real data, making its usefulness questionable.
But I am also the type who loves to see and analyze statistics. If this idea does prove popular, we should definitely consult u/Otter from lemmy.ca, who has some experience with this already.
https://lemmy.ca/post/15125231
https://lemmy.ca/post/34976449
As you can see, this is not an easy task by any means. The privacy concerns are not easily dismissed. I'm not sure if lemmy.ca has actually done their 2024 survey yet or if they are still working on it.
Good proposal though, definitely worthy for discussion.