Hepatitis C isn't a retrovirus, so I don't understand what you're saying.
It's certainly a manageable one, and the stigma around it is silly, but if the common cold is a disease, then herpes is.
https://broadly.vice.com/en_us/article/ypa8nb/did-big-pharma...
Does it really take a company to make people think of it as a disease?
"Oh my penis feels like it's on fire and oozing all over me. However, I wouldn't call it a disease."
Also the legalization of abortion in 1972 contributed to this as well.
During those times there were lots of people having lots of sex. Unwashed sex with a string scent of sandalwood and patchouli, but still lots of sex, drugs, and rock n roll.
Then you had the disco era, fueled by fruity drinks and cocaine, sideburns, and lots of finger guns. There was still a bunch of sex. Those people would become yuppies, while many of the Free Love people would have moved into the woods to eat tree bark and become one with Gaia.
Even then, knowledge of condoms wasn't widespread like it is now. My grandmother was super-pissed-off when my grandfather told her about them after she was pregnant for 18 months straight! She made it a point to tell me that I had to tell my future wife about birth control! (What made it funnier was that, at the time, if you didn't know what a condom was you were living under a very large rock!)