Actually… if you put moldy bread into soup, does it become safe?

My grandma used to throw all for moldy food into soup and she loved into her 80s completely healthy.

Not at all, food spoilage caused by mold and bacteria can have waste produced by the mold/bacteria that doesn’t break down even at high temperatures. Ex: botulism. Your grandma got lucky!

i agree with what you said with this exception :
Clostridium botulinum
en.wikipedia.org/wiki/Clostridium_botulinum → Microbiology →→ Serotypes (…)However, all types of botulinum toxin are rapidly destroyed by heating to 100 °C for 15 minutes (… )
(Heating to) 80 °C for 30 minutes also destroys BoNT.

Also : toxin is destroyed doesn’t necessarily means bacteria is also destroyed.