People active in this 'hobby' have to understand that there are certain risks involved. Those not willing to face those risks should look elsewhere for their 'sex fix'. However, there are as many people outside the biz with std's as there are with people in it.
Most people that i've heard catching an std caught it from someone they met in a bar or elsewhere. This is actually more common than not. These people with promiscuous sex habits should be getting checked as often as providers and 'johns' get tested.
As for porn, many of the male performers that you see today wearing condoms wear it for two main reasons: they have a permanent std (usually genital herpes) and don't want to infect the non-std female pornstar, and the second reason is that the female pornstar has a permanent std (again, genital herpes) and the non-std male pornstar doesn't want to risk getting it.
Pornstars who insist on performing 'with protection' usually do not last long in the biz. Safe-porn doesn't sell, and there are always performers out there willing to do anything to get the work, even if their putting their lives at risk.
As for Darren James, he didn't know that he was HIV+ when he infected others (including Mtl's own Lara Roxx). Marc Wallice, however, did know....the scumbag!!! However, what do you expect from a junkie performing in the business?