Former Imgur engineer here who worked on the desktop site and helped on mobile when I could. A lot of the code that is loaded supports features that are used by a long tail of users [1]. However, they do serve the javascript with appropriate cache-control headers and serve them from Fastly's CDN so analyzing a cold load is a bit misleading to say the least. Moreover, as other commentators have mentioned, they optimized more for the subsequent images than the initial pageloads (they'd prefetch the next N images).

Keep in mind Imgur is not a large company despite their high traffic, even at their peak of employees the engineering team was pretty small (probably about 12-15 people after series A), and the mobile web team in particular was a handful of people, with a handful of people on iOS and Android, and a handful of people on desktop/backend/API (where I worked).

That said, I think Alan does care about these things. I know at some point they did support NoScript and did care about the experience with JavaScript off (and had code to support uploading images and viewing images with no JavaScript at all). But it's hard to have it as your top priority when Reddit and Instagram are trying to eat your lunch.

I'm sympathetic with the page bloat problem and noscript and I do think more effort should be spent on optimizing this stuff, especially because bandwidth is much of their opex.

[1] Posting, voting, commenting, uploading, accounts, tagging, albums, search. There is even a hidden-ish feature to "auto-browse" in a slideshow-like manner which you can find if you crawl around the source code.