There's a fair amount of motivation to find a reason to believe it's a "the good out weighs the bad" situation. For starters they're making incredible amounts of money and then there's the desire to not think you're doing something bad.

You just need to respect human agency instead of thinking you inherently know better than the world how to use it. It is a sentiment which is very out of current zeitgeist with its "boy who cried dystopia" bent.

How do gigantic globe-spanning ad machines "respect human agency"?

I can see the argument. Nothing forces an individual to click on or engage with an advertisement

I expect it's quite easy; you believe that you're connecting people and that this is a good thing, and then you ignore the undesirable second-order effects of how you're doing it.