I agree wholeheartedly that it was in poor taste, even if it was rhetoric, satire, jest, or whatever he chooses to label it after the fact. It did get press at the time though, and was met with criticism and outrage.

I don't think the way we talk about those with whom we disagree has undergone a substantive overall change of late. Ad hominem has been around (and cheered and jeered) as long as differences of opinion have. we might be more frequently subjected to it with the onslaught of the internet and everyone now not only having an opinion and an asshole, but also a keyboard. And it's clearly in vogue in certain circles.