Q would hardly exist if Trump had not been involved in proving its legitimacy. The evidence that he was involved would be indisputable in a court of law. Not that you would ever consider the evidence. What ever Q is you can thank Trump for it. Trump who also never once said that Q was fake.
Many sincere and honest, though ingenuous, Trump supporters allowed themselves to be sucked into the Q thing. Being silent was a much better approach than insulting one’s supporters.
Trump never said it was fake because he never, ever would offend his supporters, period. I’m sure he saw it as harmless fun.