I agree that the bulk of fault lies with the advertisers themselves, but that's also the same argument spammers make - don't shoot the messenger and the such.

The reality is that it's plainly obvious to the marketer if their offers are legitimate or scams, and when this awareness is so clear it's hard to ride the moral high ground and claim innocence.

It's like giving someone a bag of candy where you know a large portion is poisonous - sure, you didn't poison the candies yourself, but to say that you're faultless IMHO is disingenuous.