Appeal to Trump Derangement Syndrome is the right's denial of how unstable and unethical he actually is. Time and time again it's been invoked and Trump's critics have been proven correct.
Even if Trump never actually invaded Greenland everything he's done so far has been completely insane anyway, in violation of ethical norms and international laws, and counter to the treaties in function. He's already crossed lines that shouldn't have been crossed ever.
No, some people on the left cannot talking about Trump, even when he is not pulling crazy shit, and we call that TDS and it has, for example, made CNN unwatchable.
That does not make Trump sane, it does not defend his actions, it is merely stating a fact.
Please, people, let's deal with the latter. That's crazy enough.