You are right, I didn't read the rules. But, as you said, I should be able as it isn't an illegal topic mentioning privacy orientated os. Should I read every line of rule of each and everything I buy/use? Definitely. Do I? Nope, and I don't think anyone does as we usually tend to apply common sense. And again, you are right, but I think, as that's the point of my post, it is nonsense having that rule in a privacy forum. It is like not being able to mention chocolate in a bakery.

A group having rule is fine, in fact it's needed for the group to sustain over time.

Unfortunately if this group is hoarding a resources, here a very popular meeting point for people who (in theory) care about "privacy" then the rule itself does not have to be "fair" or "right".

So sure, when joining a group one must aware of the rules of said group, but it does not in itself means the rules of that group are automatically correct. I'm not saying here the rule is fine (I do have a personal opinion about it) but rather that this kind of event if precisely canary in the coalmine showing the genuine nature of the group, not what its name claims to be.