Yep. Democracy is two wolves and a sheep voting on what's for dinner.
(while this is much fun...)
It's 51% of people telling the other 49% what to do.
By definition, this is
not democracy.
Democracy implies you have a constitution which exists exactly to prevent this problem.
If some so-called democracy does what you describe, it is not a democracy at all, i.e. it is either violating its own costitution, or has a fake useless constitution in the first place.
yeah, constitutions worked marvels all the time everywhere as anyone can see.
it's just a matter of scale: the bigger the political unit and the bigger the troubles that it procures to its subjects in every time and place.
Luckily what is not sustainable won't be sustained for long, since if all depended just on the wisdom of the sheeple we would be really fuck'd for eternity.