All of the lies, for example, like Trump Tells. All of the put downs, the insults that come out of his mouth, when no one agrees with him. Just using him as an example. Global climate change that is so obvious to everyone except him and his danger to the world...just as an example. His close relationship with the dictators of the world...again just as an example...
Moron - formerly a definition used in psychology and psychiatry to mean a person with a mild intellectual disability - thought at the time to be inherited - now discredited and obsolete.
Now a highly abusive term to indicate someone that someone else thinks is stupid - lacking in common sense or basic practical intelligence or nous.
But what's stupid and what's not can be a highly subjective judgement.
In my view, verbally abusing another is in itself a stupid act. It indicates a lack of respect, empathy and consideration for the other's feelings, and it does nothing to help solve whatever the problem might be.