Unless Trump's legally insane, he would indeed still be responsible for his actions (because his mental disorder isn't severe enough, as I say in the article).
What this says about his supporters is that they're abusing a mentally ill man, setting him up to fail in the end. Granted, first he succeeded spectacularly, by becoming president. But eventually, his disorder caught up to him because he'd been egged on to ever-lower depths of narcissism. And now he faces criminal trials and national humiliation (not that he's capable of feeling shame).
My point, then, which is perhaps a little facetious is that his critics (including me) should be better than Trump's supporters. We should temper our repudiations of Trump's evil by recognizing that he's likely mentally ill to boot.