A lofty ideal, but unpragmatic if you actually care about privacy. You have no control over how information disseminates once you publish it. You must assume it'll remain on the Internet forever. Even if you assume the existence of first-party deletion tools, third parties like Internet Archive or (in Reddit's case) PushShift can choose to preserve it.

If you want to retain your online anonymity, you have to be thoughtful about what you share online.