Pure Sulfa or Salvarsan drugs were far more toxic than impure crude penicillin : so what was the fuss REALLY about then ?

Before 1945, an entire generation of doctors world wide (except for perhaps a half dozen of them) were more willing to put pure but toxic sulfa or salvarsan drugs into their patients than put impure but non toxic penicillin into them.

I will go further:  an entire generation of doctors were willing to seen letting their patients DIE, rather than be seen by other doctors as putting an impure substance into those dying patients.

Fleming's non-toxic antiseptic was useless (and was called penicillin)

Toxic - but effective - antiseptic

An extremely non-toxic ,wide-spectrum (for its time)  germ-killer that can be used as a huge-dose, long term, systemic (ie something we safely introduce into the bloodstream), is a very rare indeed.

And highly valuable, even priceless, whenever our body faces massive body-wide infections that can kill us.

By contrast, what Alexander Fleming claimed to offer between the Fall of 1928 and the Fall of 1942, was a slow acting, non-toxic, wide-spectrum antiseptic (externally applied) germ-killer that was in very short supply and very unstable.