You've entirely misunderstood both Banksy's quote and the conversation on this thread. He's talking about the co-opting of _public spaces_ for advertisement; Walking down the street is an activity that anyone has a right to do with no contingencies, and he sees being "forced" to see advertising as an intrusion on that activity. Whether or not you agree with him, that's certainly an internally consistent view of things.
On the other hand, what we're talking about here is explicitly choosing to request content from a webpage and then complaining that the ads are an intrusion. There's no analogue to "walking through a public space": no fundamental right to view content that other people made on exactly the terms that you deem acceptable. As poor a comparison as it may be, the comparison to shoplifting is FAR more accurate than the comparison to what Banksy is describing.