Actually he makes perfect sense to me, it is his slides that don't make perfect sense out of context of his overall presentation. He cares because he cares about making sense, about having his name associated with something that does not make sense.
Communication is an uncertain art. You never know what people are going to do with what you tell them, even if they do get it clearly. If you don't want to take that risk, just don't give talks. If you want to play this game, though, maintaining an illusion that you have some kind of control over the ideas you're presenting once they've left your mind and turned into some kind of transmissible form (be it talking, slides, or interpretive dance) is downright false.
Consider: would Apple ever release a Jobs Keynote with slides-only. Not likely. The alternative they provide is to make the entire presentation (or select portions) available as complete AV presentations (QT or whatever).
Who cares if some guy requests your slides. If he is unable to figure out the gist of the talk, or at least the gist of snippets of the talk, then that is his problem for missing the lecture and not taking personal notes. If he's able to get some information out of it, then great, we all win and the presenter doesn't have to do much more work except provide a link.
#2 - In many cases, I've recorded or found a video of the presentation. Having the slides allows me to go back through once more.