Sorry, but I simply don't agree. You're overgeneralizing again with "everyone thinks..." but no, you will trivially find folks who believe that someone (as an example) who murders or facilitates the murder of innocent people does not deserve sympathy when they suffer the consequences of their actions.
It is not true that all rational people believe that all people deserve sympathy for all causes of suffering.
> all rational people
As soon as you find me one of these unicorns, I'll concede the point.
Like, ultimately you don't have to show compassion for other humans, but in general, life will be better for all of us if we all do.