I can definitely say that I've been guilty of seeing a subtle but not deal breaking bug in third party open source software and then failing to file a report because there's just so much to do in a day that it's easy to forget. It's on all of us to be good open source citizens.
I think the counter point of this is being kind when people report bugs that aren't bugs.
If users encounter a weird result, report it, and have someone call them an idiot because they misunderstood a nuance of the system... they'reβ probably not going to take the time to report next time around.
(And I get it, there's that common issue that people consistently misunderstand and you continually get reports about. But each one of those users might also be a user who finds a real bug next time.)
I think your parenthetical probably explains the dismissive attitude many upstreams have, but I would argue that if so many people are (consistently) misunderstanding your software then there's probably a UI/UX/education problem that needs fixin'...
