Critical distinction, people freely choose to install AdBlock Plus. There are already alternatives, and the barrier to entry for new competitors is pretty low. This is unlike the ISP market, which is not meaningfully competitive in a good chunk of the world.
In my area, if Charter and CenturyLink both chose to de-prioritize Netflix traffic, that would be the end of it. I would have no economic alternative. But if AdBlock Plus started showing me ads that annoyed me, I could just go download a different adblocker.
 I don't actually use AdBlock Plus. I use AdBlock for Chrome, which is a separate product.