"Know of any good explanation for why news sites are so bogged down?"

So you'll probably get cynical answers about lazy programmers and such, and there's some truth, but I'd suggest the dominant problem here is that the specification of the Web has very little consideration for possible performance built into it. Browsers are basically enormous constraint satisfaction engines, and that's intrinsically a fairly slow operation. Combine that with, well, a lot of the issues that HTTP2 is trying to address like requests for lots of small little resources, flash plugins written with their own programmer-easy-but-computer-expensive shortcuts, and the whole thing is very hard. Browsers are probably more "miraculously fast" for what they are being asked to do than surprisingly slow.