"It's a little facile to just write off Stalin as a despotic monster."

I took that to mean he disagreed with the description, and that is a reasonable assumption which he could easily have corrected.

Instead he just said, "Of course he was a despot, but..."

I took that to mean he agreed with despot but disagreed monster.
Again, a reasonable assumption which he could easily have corrected, but chose not to.

That could not be described as sending the thread astray.
It was establishing our views of Stalin.