You're forgetting that the issue is perceived value. If the advertiser *thinks* showing you an ad has value, then money will change hands from the advertiser to the site. In the long run, if the advertiser is wrong, they simply stop showing ads in places where they don't work.
>Also, maybe I get so tired of seeing the same car ad every 10 minutes in a Hulu video that I start to hate that car and its manufacturer?
Yes, this is typically known as banner burnout and most advertising systems have a way to cap how frequently a given user is shown an ad. In general, though, they need to have stored a cookie to remember who you are. The great irony of blocking ad cookies is that you look like a nobody to the advertisers. A nobody isn't worth anything special, so you get the cheapest ads in the system, which are usually the obnoxious, carpet-bombed ads.
And the advertiser would LOVE to know that you're not interested in cars so they can avoid wasting their money. Trust me, advertiser are aware of ALL of these issues. Whether they handle them well is a separate issue.
> If some people are so hostile to advertising that they use AdBlock, why not leave them alone?
Maybe because they're effectively leeching off of the website? If the site has advertising, it's trying to make money and showing ads is party of the implied contract of visiting the site (unless they have a paid "no-ads" option). You can break your end of that contract with little consequence, but you shouldn't expect the site owners or advertisers to be happy about it. :)
In general, I don't think people are hostile to all advertising. They're hostile to poor, obnoxious, irrelevant advertising. If AdBlock Plus is using its weight to make advertising more user-friendly and effective, that's a long-term win for everybody (unless you'd rather be paying websites directly, which is a truly viable options often available to you now).