Obviously, there will always be some unestablished websites claiming to be the "be all end all" for your money troubles or the "#1 authority in internet marketing" and other such garbage, but the legitimate companies who have thousands of reviews to back it up are not "abusive" in your definition of persuading people to purchase a service, because the act of persuasion is not inherently abusive.
It is abusive if a site were to persuade a viewer to purchase a sketchy product or service (as many scams do) and fail to fulfill their promises to a satisfactory level. Then, laws have been broken and, technically, one could take them to court and sue if their TOS is not robust enough. Even then, a clever lawyer can find a way to incur reimbursements for unaccounted damages in said TOS.
Being persuasive for the sake of marketing and being persuasive for the sake of scamming (read: "abuse") are two different things. Do not mix them into the same category, that is generalizing and is highly frowned upon.
If a product or service seems sketchy and you fail to heed the reviews on it, or you take a risk with a new service that may very well be extremely high risk for you, then you are the one at fault if they are not legitimate. As with all things on the internet, buyer beware.