Ok. He was obviously wrong. He made a prediction about the future and was wrong.

But to say because he was wrong this time, he "didn't have sufficient knowledge" is just kind of dumb itself.

He's probably way more aware of what Ukrainians are feeling about the situation and their opinions on what's happening than we are. You can have a lot of knowledge, but still be wrong. Lambasting people and insulting them for the apparent sin of simply being wrong is the thing that's degraded and limited useful discourse.