Alex Jones wasnt the mastermind who created this conspiracy theory. The crisis actors conspiracy theory was already popular on the internet a couple days after the incident, months to years before Alex Jones covered it. There were numerous people speculating at the time about some strange discrepencies in the official narrative and footage which was able to convince some otherwise very reasonable people that there was a possibility that it was a hoax. So no, it cant be said for certain that he knew it was false. And no, he cant be blamed for covering a popular conspiracy theory on his show when its well known that he performs a conspiracy theory talkshow. I dont understand why this whole conspiracy which already existed is being attributed to Alex Jones. Perhaps just because he has a popular show? This is a clear case of punishing a citizen for having the wrong opinion.
I'm pretty sure it's a clear case of punishing a citizen for building a hundred million dollar supplement business on false allegations about the parents of dead children that were made so repeatedly they had to go into hiding, and then boycotting the resulting defamation trial. But tomato, tomahto.
Five minutes of research shows that this isn't true and that he knew.
I'm not sure anyone is seriously attributing the conspiracy theory to him, they are attributing to him that he spread it, publicly attacking the families while making money doing so.