And I would say there is no way to ask that question in good faith. (Tedious proof by cases left as an exercise for readers.)

The correct question would have been, does anyone else agree with the statement.

In this particular case, the amount knowledge needed (of e.g. Lean language, math and Erdos problems) means any credible statement about the difficulty requires an expert.

"Are you an expert?" is a perfectly respectful question.