> I don't understand why the default behavior isn't to isolate every website from every other website? Why is least privacy the default?
Default privacy settings are tough to manage.
Some people want privacy, and will accept broken websites if it keeps their data and online movement private.
Other people just want their usual websites to work, don't understand or care to think about privacy, and if some random content farm looks busted in Firefox, will just switch to another browser.
Aside from picking a sensible default, Firefox also offers to educate users where it makes sense. For example, when you open a new private browsing window in Firefox, the tracking protection section includes a "See how it works" button that takes you to a tour-style walkthrough of how tracking protection works.
Default privacy settings are tough to manage.
Some people want privacy, and will accept broken websites if it keeps their data and online movement private.
Other people just want their usual websites to work, don't understand or care to think about privacy, and if some random content farm looks busted in Firefox, will just switch to another browser.
Aside from picking a sensible default, Firefox also offers to educate users where it makes sense. For example, when you open a new private browsing window in Firefox, the tracking protection section includes a "See how it works" button that takes you to a tour-style walkthrough of how tracking protection works.