I agree with you: anyone who is talking on the internet about a p[articular coin, has some hidden agenda, related to himself. Whether it is "popular coin", "hyped project", "person has holdings of this coin", "pump and dump", or similar reasons.
On the other hand, some coins, or tokens are designed that way. So people "spread the good word" and instead of company spending money direct for advertising, they can allocate that budget to the members (coin holders).