One reason we beat donks is because they only see the strength of their own hand. I would find trip aces with A2 here pretty much as easy to fold as Ace high on an unpaired board, but donks don't, and your example is effectively looking at the same concept.
And this is the confusing element. I lost 2 big cash pots holding an underdog full house, on fairly innocuous boards too - no broadways. Then I folded 2 full houses that would have cleaned out my opponents because, as you said, they only saw what theyhad - which was two pair - and not the risk of a full house. They insta raised all in and I instafolded both times, sure they'd hit their K and A full houses. They didn't. And I felt like crying, lol



And as for your going broke comments, then it is worthwhile betting out to scare off Mr J4.