The fundamental problem here is a little broader than ads, but "ads" mostly cover it. The problem is the commoditization of human attention. The incentive to catch and sell attention is poisonous to all human endeavors. Some things need to grab your attention to fulfill their purpose, I'm not against the idea of something directing a person's attention. Where it becomes a problem is the murky line of that direction of attention being something that is bottled and sold, or otherwise used in the interest of the distracter rather than the distracted.

So ads that someone seeks out of their own volition? Fine. That's just marketing material, and falls in the same category as every product announcement, press release, etc. What if a product catalog is mixed in with coupons or other rewards? Not fine anymore, you've mixed up reward-seeking and information-seeking.

If someone means to direct their attention and gets distracted by an important notice, like "I mean to drive down this road, and the stop sign grabbed my attention," that's also fine. The information is relevant to the human and important for augmenting their intention. But if you download an app and try to do something, only to be met with a banner/popup/whatever informing you of other products on offer by the company? Well, they're not selling your attention to third parties, but they are monetizing it by taking your intention to use one product and attempting to redirect it into a potential purchase of another, so that's out. If you want, you can include a clearly-labelled "our other offerings" section in the app, out of the way, somewhere it would only be encountered by someone seeking it out.

Distracting people cannot be allowed to be one of the main drivers of our economy.