> What is legit or scientific about it?

Nothing. And no one here is claiming that all parts of these texts are to be taken as absolute fact with empirical proof. Most of it, as you mention, is riddled with imaginary stories probably because scientific discovery was being carried out by religious philosophers of that time.

However, there are parts of these texts that are legitimately impressive, philosophically or scientifically - and a blanket denial of that would be just as unjust as the 'filth'.