A person's reputation is not what is in their signature line, it is how they act and what they say. Having a paid signature is nothing more then receiving money for advertising a good or a service. If you are against advertisements then you should be against this forum (that sells ads) and any source of media/news as they make almost all their money from advertisers.
Yes, a person's reputation is based upon what they say. When you *sign* your posts with an ad for some product or service, you are *saying* that you endorse said product or service.
The only thing that these people are saying, by accepting to rent their signature space, is that they need the money. Nothing else.