First of all, was it made clear whether the model in question was shooting the scene with or without a condom while he was in Vegas? Condoms are only 85 percent effective, true, but let's not start making people panic until we know all the facts.
Secondly, it is worth noting that about 85 to 90 percent of the gay adult industry REQUIRES that its model use condoms during filming. This is how we get around the testing; we actually promote safe sex in our videos, unlike a lot of straight producers that still don't.
Additionally, there are lots of gay-for-pay performers who identify as straight, and have been for a very long time. Everyone knows that at least one MAJOR icon of male heterosexuality (whose name I will not publish since he's been known to throw a hissy fit whenever it's brought up) started out in gay porn under a different name, and took some MIGHTY big ones up his butt like a champ. Bigger than I've ever taken.
The money in gay porn is much better for male performers. And with nudie girl mags, Viagra and dick injections, performing in gay videos has become even more frequent for straight models. If you guys paid your models better, maybe they wouldn't have to keep doing gay movies.