It’s not that complicated. A lot of people don’t like condoms, either wearing them or having a partner wear them. PrEP, to many, has rendered condoms unnecessary.
A lot of people out there have managed to get past stigmatizing STIs, viewing bacterial ones as no more remarkable than sinusitis so long as they get tested and treated.
Between PrEP and vaccines for hepatitis and HPV, risks for the scariest STIs can be annulled, outside of exceptional, treatment-resistant cases.