Well, historically ad revenue for TV is based on viewership, right? I’m not 100% sure how that was calculated before streaming, but I would think that changing the channel would still affect those numbers, albeit in a more gradual way. It would still have a similar effect, just not as immediate.
It’s important to differentiate “immoral” from “consequences.” The consequences of adblockers/changing the channel is that it may impact content creators, but that doesn’t make it immoral.