"I suspect most people use AdBlock not because of ads but because of the degraded performance"
Oh come on. Practically speaking, "most people" don't care about the "degradation" of a site due to Javascript. Most people wouldn't even know what that meant.
They don't need to know what it means. They just need to notice "with ads" = slow, "without ads" = fast, and even if the visual presence of ads doesn't bug them, they still see a win with AdBlock.
I think that people blame the ads for the performance and experience issues and that's what causes them to search for ad blockers rather than the getting rid of ads for the sake of getting rid of ads. I might of course be wrong.
Most explanations for Adblock are made in terms of HTTP Requests, so most people are concerned with performance. They may not know all the full story, as the typical web dev likely would, but your characterization is not offbase nor unjustified.
In any event, MrPleb's dismissive response is unwarranted.
Oh come on. Practically speaking, "most people" don't care about the "degradation" of a site due to Javascript. Most people wouldn't even know what that meant.