Why would one want to disable JavaScript in the first place? Privacy & security: why enable a site to execute random code on one's own machine when all one wants to do is read some content?

There are many reasons. Another is this: on most webpages (i.e. places you go to read text and maybe images and some videos; as opposed to web applications), JavaScript is an unnecessary waste of processing power, that only makes it harder for you to read in peace. It doesn't add value for user, so there's no reason to have it running in your browser.