No, that's not the reason, given that PrEP exists. The actual reason is that Truvada, like other healthcare, can be hard to get in the American system.
Have we considered telling people to "just stay home" and to "not have sex"? Maybe that's the trick.
Right. Abstinence doesn't really work in the real world, only in the spherical-cow world where humans are perfectly obedient.
Isn't that a tacit argument against stay-at-home orders?
Yeah, I'm persuaded by the Julia Marcus school of thought that simply ordering people to stay home is important but not nearly enough. You have to provide ways for people to reduce their risk in case they decide not to listen to your orders.
I personally stay home as much as I can, but I have certain privileges many others don't.
No, that's the strategy for lower-caste straight people. Telling them that leads to socioeconomically capturing a large percentage of them by burdening them with children before they can hit early potential.
Telling people to not ever have sex is different from telling people to not meet in large groups during an acute and temporary pandemic. Especially when you only forbid sex for a subset of the population while the remainder of the population is allowed to have sex. The group ban on the other hand is mostly unrestricted and thus more fair.
The incidence rate of HIV infection is the same in the US as it is in France, Span, or Italy though higher than the Scandinavian countries. I couldn't easily find data for the current rate of new infections, but its not immediately obvious to me that access to health care is the major driving factor.
I don't know enough to comment on European countries, but I wouldn't be surprised if access was a big problem there as well. The American healthcare system is pretty bad, but it's not the only bad system in existence. There may be other linked factors like stigma at play as well.
Condoms also exist, and are trivial to buy, in the American system.
And I'm sure transmission rates would be even higher if condoms were harder to get.