Philip Bump at the Post says why Trump’s failure to disavow QAnon is so dangerous:

The FBI was concerned enough about the emergence of “anti-government, identity based, and fringe political conspiracy theories” last May that it issued a formal intelligence bulletin to American law enforcement agencies. It warned of people being inspired to engage in “criminal and sometimes violent activity” by such philosophies, given that they “tacitly support or legitimize violent action.”

So Trump thinks they sound nice.

The spread of QAnon is seen by federal law enforcement as a threat to the public. There are obvious cases in which QAnon is used by disturbed individuals as a rationale for their action, as in the murder of a reputed Mob boss on Staten Island last year. This is the central concern, that fostering a belief that there exists a particularly evil group — its members defined by individual observers — will lead to some of those observers taking steps to confront the presumed evil. That some QAnon adherent will decide that some other person is part of the cabal Q is discussing. That is allegedly what happened on Staten Island.

Trump could have said that the theory was obviously not true and itself stood as a danger. He could have fervently denied that he or anyone in his administration was involved in any action like that Q describes. He could have indicated that his government was taking steps to contain the theory. But he didn’t. QAnon adherents like him and, hey, what’s wrong with being seen as a guy who wants to take on Satanic pedophiles?

Somebody has to, right? If they’re there. Anon says they are, and who is Trump to contradict them? They like him. He has no conceivable reason to contradict them.