The problem is that a *professional* knows that they could lose their license for diagnosing someone who is:

A) not their patient
B) not someone they are sitting down beside
C) probably willing to sue over HIPPA violations for revealing a diagnosis.

The real problem is the media, who continually legitimizes Trump because they want those sweet, sweet clicks.  The real problem is social media, who are incentivized to radicalize users for engagement, and who know right wing extremism is the easiest path towards user retention.