no. Marketing does not need to be manipulative or deceptive. In fact, if you are not anonymous and not going away when the company dies, deceptive or manipulative marketing is probably not long-term effective.

Pointing out that you exist and that your price is X and some other measurable attribute is Y is ethical, I think, assuming you use consensual channels, and that your price is in fact X and your other measurable attribute is in fact Y.

So yes, good marketing is honest and is important for both the buyer and the seller.