Much of the opposition seemed to come from a vengeful kind of religious conservative who wants sex to have negative consequences. Those conservatives represent a familiar kind of evil.
Yet I suspect that some opposition also came from women who had a problem with protecting men's sexual health. This is a newer kind of evil, and even less sensible for women who are heterosexual, for the herd-immunity reasons I outlined in my first paragraph.
A more-widely-administered HPV vaccine was literally a win-win for everyone, gay and straight, female and male, and still it came about slowly and faced opposition. This made me despair of my fellow humans.
But sure, that works when people do it. Just like social distancing.
Relying on other people's good behavior at a large scale is a bad plan though.
Also not sure which number of partners brings the most frustration or alienation. One? Three? Zero? Each situation seems to bring its own problems. Life is suffering.
("One" is the best plan for most people, but it depends a lot on which one...)