They don't use it to signal eachother. They use it to bait handicaps like you so your side looks insane by comparison to a moderate. You clearly don't know what you're talking about. But whatever, more usefuls idiots for the right to use I guess.
The actual intention of these things is to get useful idiots in the centre to spread them around without even knowing the full meaning behind it. A great example of this is the "it's okay to be white" poster. Of course it's okay to be white, any sane person will agree with that. The problem is that the message was adopted and then promoted by actual national socialists, and centrists/apolitical people will spread around the poster on social media as if it's some harmless message. A group of people who are already familiar with it's background will think the person who posted it is in the know, even though they are clearly just naive. I will agree with you in that some lefties are terrible at this and will fall into the bait and start calling everybody who uses a pepe a full blown national socialist. Disappointed that you think that of me though.
I was one of those useful idiots who saw a message that said "it's okay to be white" and thought "why would these people be disagreeing with this?", completely oblivious to the fact that I was spreading a message that was literally
being promoted by neo-national socialists.