Not sure exactly what you mean with social conservatism, but I'd rather call out misplaced optimism.
In the past the approch was to only target young girls before they had sex for the first time, which turned out to not reduce the spread of HPV as much as hoped. Only in recent years the recommendation changed to also vaccinate boys and increasingly also people with previous sexual encounters.
> Not sure exactly what you mean with social conservatism
"This is also why social conservatives don't like it when scientific progress makes sex safer or better. Sex outside of their ideal scenario (in marriage, at the husband's wish, for reproduction) should be punished, and steps to mitigate that punishment (STD prevention, pregnancy prevention) should be discouraged or lambasted as immoral."
In the past the approch was to only target young girls before they had sex for the first time, which turned out to not reduce the spread of HPV as much as hoped. Only in recent years the recommendation changed to also vaccinate boys and increasingly also people with previous sexual encounters.