In ATLA, there’s an infamous episode called The Great Divide.
Aang tells a lie to get two tribes to stop fighting a pointless feud that’s been going on a hundred years or so. And the fandom seems to get all huffy about that.
I think he did the right thing. If there’s nothing to prove he’s lying about how the feud began, then there’s nothing to prove about why it should continue either.
No I absolutely do have a problem with the ‘All’ part. Don’t presume that everyone agrees with that rhetoric.