technically signing up for any service gets you put on a list, and there are very few lists anyone has - including handwritten ones in your kitchen drawer - that the government/police couldn’t access if they really wanted to.

Privacy, safety, security are conventions and habits of politeness mostly.

Really the main protection is that there are much bigger fish to fry than people reading internet posts about politics, and even within anarcho-social circles, there are bigger players with more concerning activities than you.