Are all Paladins Lawful Stupid? Yes,
No, they aren't, why don't you stop lumping all paladins together... the same way that Larian literally lumps all paladins together and makes them follow their version and understanding of a specific oath that has very little to do with the oaths actually taken?
Lawful is not a requirement, nor is Good, for Any paladin.
The bugs that many report tie in to the fact that ALL paladins, regardless of oath choice, are often being treated as, and given oath breaks for, breaching the devotion tenets, even when they are not devotion paladins.
Other bugs include murdering a creature causing an oath break if it dies to the smite damage, but not if it dies to the weapon damage, or getting an oath break when your allies kill a creature that was part of a literal ambush trying to kill you, before said paladin has any turn or opportunity to do or say anything anyway.
Your example is inaccurate to the current game, or at very least is buggy and inconsistent in replication based on other poorly implemented elements.
