>Why don't Firefox add a dialogue to their installer allowing normal, private and paranoid options?
Because they make money out of your data.
>Can we do anything about it?
There is GNU Icecat, it is pure of that shit.
https://www.gnu.org/software/gnuzilla/
https://spyware.neocities.org/articles/icecat.html
But there is something wrong anout web standards and browsers at all - they're so bloated, almost no one aside from big corporations, can maintain them, and that's probably on purpose. If it's big and you can't understand it, they controll it. Also it is easy to hide (((unintentional bugs))), that can be exploited, to crack and then use browser against it's user.