The worry about possible long term effects is legitimate (but not very significant, considering these drugs have been in use for quite a while for other purposes)
But, "it's not natural" complaints are, frankly, bullshit. Nothing about how humans live today is "natural" and we're better off for it.
> We already have built-in "ozympic" functions
The drug works by literally making it mentally easier to eat less. It's caffeine for discipline instead of energy. There's no "built-in" that works like that.