I'm sure you're right about the probability that many small business owners would still behave honorably if problems were brought to their attention first, but GP was, verbatim, referring to "bad charges coming in from the vendor," and "fraudulent or even mistaken charges," which is quite different than the negligent-customers scenario you're describing.

Edit: Not to mention that GP is referring to an anecdote of GGP's in which Amazon told him to dispute the charge because they couldn't sort it out. That's disgraceful.