That's great, but I want to talk/share things with anonymous strangers who aren't my friends who share the same disease I have. That's my need, not this. This is superfluous.
Did you try to find a subreddit concerning the subject you're interested in?
What a devastating one-two punch, (1) to have a disease and (2) to find out reddit is the place you have to turn.
Reddit has a lot of active, helpful communities hidden away in smaller subreddits. It's really only the default subreddits and other huge subreddits that are bad.
It's the same people, check their comment histories some time
Allowing anonymous users would be great. For example I would like to create such a group/space for my family even though some of them do not have google accounts.