> The Internet archive is a 501c(3) corporation, isn't it?

That's just the way the US tax code labels it. The main distinction is that as a non-profit, single-purpose organization the Internet Archive exists only to archive things and isn't subject to changing shareholder whims or takeovers.

It's much easier to imagine e.g. Google getting pressure to drop Google Books if it was deemed unprofitable.

Why would you turn off JavaScript?

Security and better performance on cheap hardware are two reasons I turn it off by default and only enable it when I really need it.

You should turn it on when browsing archive.org - you'll really need it.