This isn’t a mere semantic quibble. It’s a blatant misrepresentation of what was done, with an attack based on that.

To make an analogy to gun control, imagine if a prominent person said that the Parkland attacker constructed the bomb he used to kill all those kids with a rare explosive that can only be obtained from the government of Ecuador, and implied there was something funny going on. Should we avoid calling this “false” because he did actually kill a bunch of kids?