I think there is two levels to this.
One is advertising BB to attract mugs into scams and whatever. I believe a high percentage of the fake profiles on AW have BB thrown in as a 'like' - why wouldn't they. It would tend to attract the er, intellectually challenged, which is precisely their target market.
There also seem to be a subculture of BB activity going on, which the 'respectable' sex industry regards with similar distaste to that which society at large regards the sex industry as a whole. Kind of ironic really.
I doubt there is actually such a thing as a bareback gang, although like the OP I find the concept quite funny. I've no doubt there are a number of girls who entice punters into BB on the basis that they will want to continue to see them for it. I have had it suggested to me too many times for that not to be the case. As long as they carry on with it out of sight and it doesn't affect me I'm not bothered too much. I do understand it, because some people do want it no matter what the cost, even girls, so that's up to them because at our level we do things that the rest of society disapproves of, so the same principles apply. The danger is when the BB participants circulate among the rest and pass things on by way of other routes such as oral sex. Fortunately HIV isn't easily transmitted that way, but there's a whole lot of other nasties that are. What is it they say - 'buyer beware', or something like that.