I disagree entirely that stealing from a corner store and not rendering ads are comparable. In one instance, I take an item that another person has paid for and expects to sell it at a profit. If I steal it, I am depriving the store owner of that item and the profit they would have made.

If I choose to view free content and not render ads, no one has lost anything. While yes, the site owner does not get the profit from "selling the ad", it is not theft in the same way if I were to walk into a store, look around, and not buy anything is not theft.