If you read a book that tries to change you for the better and it fails or doesn't resonate, then it's a self-help book.
If you read a book that actually succeeds in changing you for the better, then the label changes from self-help book to great book.
We don't like books that fail, because they waste our time, they offend us, they speak a different language or they make us feel out of sorts. Self-help books are a bane.
On the other hand, a book that resonates with us, whether it's Catcher in the Rye, The War of Art or Zen and the Art of Motorcycle Maintenance earns a place of trust and we revere it and tell others.
A store clerk who tries to sell you something and fails is a high-pressure salesperson.
If she succeeds in selling you something, she's helpful.
The difference between the two categories isn't one of intent. They're all ultimately trying for the same thing. The difference is in success. So, go ahead and denigrate self-help books and salespeople and the rest. Just be clear with yourself that what you're unhappy with are the ones that fail.
By the way, the only real help is self-help. Anything else is just designed to get you to the point where you can help yourself.