I wonder how could any Facebook replacement (or Facebook itself) allow somebody to support some group while not telling anyone. Of course it's possible, donate some money, do some job for them, but… on Facebook or something like Facebook? How?
Ironically, right before the big push to erode users' privacy, it seemed that they might have taken it a step further and replaced your name with "facebook user", removing even your first name (I was never sure if this was intentional or a bug, but in any case it didn't last long as the big privacy changes came soon after).
We know how valuable the data is and what can be done with it, that makes us much more sensitive to giving it up.