My argument here is that product reviews become more like advertising once they start being edited or selected for marketing purposes. So e.g. Amazon's reviews

My argument here is that product reviews become more like advertising once they start being edited or selected for marketing purposes. So e.g. Amazon's reviews do not appear to be advertising, which would make it misleading to bias them in some way. And the rules for what's acceptable in advertising might be different from what's acceptable in providing a neutral forum for customer reviews.