All ad blockers do is block common ad servers. They don't generally work on websites where the ads are hosted on the same server as the content because if the content and the ads are both coming from the same server then there's no reliable way to distinguish between the content you requested and the content you didn't.
Sometimes it can be done on a case by case basis by visibly blocking out regions of the page where ads normally appear, but that too can be easily thwarted by randomizing the placement of the ads.
All things considered, preventing ad blockers from working properly is far from impossible. It's trivially easy.