There are literally psychologists working to use our brain’s design to their benefit. It’s not entirely fair to criticize someone for being manipulated by highly trained experts who labor to manipulate them.
If you are repulsed by sales as an activity, I can see how you'd arrive at the "manipulation" point of view. However, I would much prefer this type of "manipulation" to being hard sold in a car dealership, for example, or having to endure cold calls from strangers. Undesired synchronous sales interactions are much more emotionally draining than seeing computer-generated ads online, IMHO.