Because you can't choose what's acceptable, they do.
You won't decide the topic, format, quantity, density, duration, nature or interruption type. Which is different for you, me, or your children.
What's more, ads are not made for your benefit, ever, but to the benefit of the advertiser which may (but statistically more likely may not) align with yours.
And also because:
- the incentive gets twisted, which means you can't trust ublock on the long run.
- unkown unknowns means down the road, some ads will manage to track you or serve malicious content despite ublock filtering.
- ads paid content is a terrible business model which take a price people are not wired to assess nor realize they pay for something they disguise as free yet has an impact on the entire society. Not a great thing to encourage.
And I say all that as someone who gets revenue from ads.