> If a webpage is a billboard, then it is morally wrong for me to paint over those sections of the billboard that I do not like (i.e., using an ad-blocker). This viewpoint is held by those who own webpages (because they want control over it) and by those who cannot change what a webpage looks like (common users).

Why is it morally wrong to paint over billboards?

But even if we accept that unfounded premise, the equivalent of ad blocking would be to hold something in front your eyes blocking the billboard as an ad blocker does not prevent other visitors from seeing the ads but paint does.