The ad blockers are for behavioural ads. The api end-points which tracks you through tabs, listens to what you are saying through your phone's microphone.

Not contextual ads which you will setup for just your website / app. They are just <img> tags or equivalent. The entire reason why people use ad-blockers are because it is bad UX, anti-privacy and just sheer garbage amount of data gathering. Use a website with and without ad-blockers. You will see the difference. With middlemen comes problems for users.