So people fiddle with the settings and the browser "breaks?" Is there some reason it wasn't possible to create a button reading, "Restore Factory Settings," in large, friendly letters? Or was that too hard?
The simple answer is that there is a growing movement to reduce user options that can break applications.
Please try to remember whose machine you're running on. You're a guest under my roof, and guests that behave badly do not get invited back. So no, you don't get to run code in my browser until you've earned a certain level of trust, and you certainly don't get to invite in your friends' code. (I mean, just who the fsck is rpxnow.com, anyway?)
For example, there are websites that not only don't work without JavaScript, but they fail in complex ways [ ... ]
The technical term for sites that behave this way is, "Broken."
Hence, once you remove the disable JavaScript option Firefox suddenly works on a lot of websites.
Firefox already works on a lot of Web sites. Is someone shipping FF with JavaScript turned off by default? What exactly is the alleged problem here?
Today there are a lot of programmers of the opinion that if the user has JavaScript off then its their own fault and consuming the page without JavaScript is as silly as trying to consume it without HTML."
These programmers are called, "Wrong."
Back in the 1990's -- in the days of sneaker-net, recall -- macros in Microsoft Word documents, originally thought to be oh so terribly clever, proved to be a monumental nightmare for their ability to spread viruses and generally wreak havoc. It was so bad that even Microsoft was forced to admit it fscked up, and no longer executed macros in a loaded document by default, but would ask first. So you'd think the lesson on embedding executable content in what was fundamentally a document would have been learned.
Then some allegedly clever person kluges together JavaScript in an afternoon, and suddenly executable content embedded in documents -- over a genuine network, mind -- becomes a fantabulous idea again.
Uh, no, it didn't. JavaScript was a stupid idea, and should never have been allowed to happen. Unless your site is trustworthy and useful, you DO NOT GET TO RUN JAVASCRIPT.