despite the positive changes in today's Firefox release, it's worth remembering that time Firefox decided the GUI options for disabling sslv3 should be removed http://forums.mozillazine.org/viewtopic.php?f=23&t=2722163
(1) It sped up the implementation of TLS 1.1 and TLS 1.2. Removing the UI meant I didn't have to redo the UI when I added TLS 1.1 and TLS 1.2 support. Keeping that UI would have caused TLS 1.1 and TLS 1.2 to be delayed even further.
(2) Our measurements showed that ~1% of users had disabled TLS 1.0, leaving only SSL 3.0 enabled. I was worried that the UI encouraged people to make that mistake. Also, it is the application's responsibility to do the right thing automatically. People shouldn't have to fiddle with such options to be secure.
i wouldn't dispute that disabling sslv3 gui prefs in Firefox may have had significant positive impacts on many users or that many users are clueless about crypto in general as it seems you're implying, but it's worth considering that those decisions also have implications that may be convenient for other parties, like dramatically increasing the activation energy to configuring a browser for security.
another example is how long it currently takes to configure via GUI distrusting or at least warning users when Firefox relies on CAs that users from a given country may almost never encounter. should your average Firefox user in the United States always silently trust Turkmenistan's CA out of the box?