Lots of pages, news-sites in particular, use JS to load more bloat, animated slide-decks and lots of things causing slower loads, including "beacons", and lots of fancy/noisy UI-elements distracting from what you actually came for: the nice, static HTML content that was the news.

You will be shocked to see most pages on the internet load almost instantly the second you disable JS instead of spending several seconds loading all sorts of non-content.

The performance gain of disabling JS is immense.

I think it is because performance. Visit techcrunch (23) or huffingtonpost(30+) for example with an extension like ghostery which shows how many external js lib gets loaded. I don't block js but I block flash and it is for the same reason.

My record is around 40+.

I don't know why do they need that many. See reddit, loads 2 I think.

I feel the web runs a lot smoother for me without JS. I don't get pop-ups, bulky advertisements, or other resource hogs that detract from content. I also don't like that Google or Facebook are tracking my movement across websites.

I am not OP but my reasons are security, ad/tracking breaking and general peace of mind. With the latter I mean for example popups, unnecessary animations, you might also like, CPU overload and other modern webdesign features.

speed improvements, privacy and the sense that the web should work without javascript, damnit. that said, js enabled+ghostery works well enough in Opera for me that I've started browsing with it on by default again.