I don't think he understands or cares. He is not going to be affected by made up stories about him in any significant way, but it makes it that much harder to bring truth back into politics. If you actually manage to fool one of his supporters and they find out about it, it will only make Trump's propaganda stronger. Meanwhile if you fool someone against him and they try to cite it, they'll lose credibility.

Trump deserves a lot of things but this one actively hurts people's ability to push back against him.

Just add a /s or satire tag to things. Have your fun without confusing people and muddying the waters