I don't.
The argument for adblockers being a form of piracy is that there is an implicit contract. The content creator gives us the permission to watch the content with the implied requirement that we watch the ad that comes with it. So, we are paying for the content with our time and attention when watching the ad. By using an adblocker, we refuse to pay this price, violating the terms of the implied contract, thereby forgoing the permission to watch it. In this argument, the definition of piracy used is that of using (by watching) a work protected by copyright without permission.
I don't agree that there is an implied contract for watching an ad any more than there is an implied contract for watching the full video. Not watching a full video impacts the statistics of the creator in a negative way, so there is an implied contract that if you begin watching the video you will watch it all. By this logic, it is also a form of piracy to stop watching. There are many things that the creator or YouTube might like you to do, but that does not spawn an implied contract. If they want a contract, they will have to add it to YouTube's ToS. Then it might be piracy by some of the looser definitions.