We should take every opportunity to worsen their lives as they have employed themselves to worsen ours.
Just to play devil's advocate for a second. Some times you don't do things that would benefit you. In these cases getting your to do something that you wouldn't otherwise do is beneficial.
Which is something that marketing very nearly never does.
Marketing does more than just create ads: they research what their customers want, what they say they want vs. what they actually buy, and it doesn't matter how good your product is if no one knows about it.
The problem is that there are almost always other companies making the same/similar products, so you create a race-to-the-bottom effect where you have to eventually get more and more crazy in your methods of reaching a target audience. Don't blame marketing, blame capitalism.
I can blame both, as well as the underlying sociopathic mechanisms that the modern understanding of the terms necessitate.
If I am not mistaken what you are describing is market research, not marketing. Marketing is, in practice if not theory, about invasion of attention and manipulation. If marketing were not these things then companies would be content to have their products discovered in catalogs and store shelves where interested parties willing to devote attention to such things would readily find them.