Fast-forward to 2009 and Twitter is loved by these same outraged readers despite the fact it functions often as a partial feed RSS. It's the return of the click! People don't mind now actually visiting a website. I think of my own experience with TechCrunch - pre-Twitter i'd consume 99% of their content in my reader. Now i'm more likely to click on a Tweet and go to their website if there's something of immediate interest, and their feed has become non-timely catch up consumption.
Why do geeks hate partial feed RSS but love Twitter? Because in their mind Twitter's truncation of content delivery isn't a violation of the internet - it's a technical limitation based on the service's SMS origins. No pointy head suit is making the decision to limit their feed in order to monetize you on their site.
So of course the totally illogical reality is that when consuming content on your iPhone, Publisher XYZ's partial feed in your Reader app makes you mad, but Publisher XYZ tweeting the headline and link to their new post makes you happy. Same experience, different context, different user reactions.