According to the study, people expect that a PrEP regimen would be something that they could take before having sex that would be highly effective at preventing HIV. I can't disagree with them - that's what PrEP should ideally be. The PrEP regiment that was tested, however, was a daily regimen of anti-viral pills that reduced actual transmission rates by less than half. In other words, it's an entirely different kettle of fish.
Asking people to take a pill every day of their lives on the chance that one day they may end up having sex with a person with HIV, without being able to offer more than a 50% reduction in risk of such an encounter occurs... is asking a lot. Particularly since by practicing safe sex they can get a much more significant reduction, and that's something they don't need to worry about in advance.
A magic pill that did what people want would, in fact, be an incredible tool in the HIV prevention regimen, but the current state of PrEP doesn't provide that magic pill. Furthermore, I continue to have trouble believing that there is a large population of high-risk men who will be more consistent about taking a daily pill than they are about practicing safe sex -- particularly when doing so doesn't convey nearly as strong an advantage against HIV infection.
I'm willing to be proven wrong, but the whole PrEP scenario still feels like a losing proposition designed to give people an excuse not to practice safe sex without doing a great job of reducing their risk.