The same reason why Windows 10 and Chrome exist. Nobody bothered to read the license agreement. But, unlike Google and MS, Mozilla respects your freedom to disable all the stuff you don't need.
At least jewgle are upfront about how shitty they are
cuckzilla still tries to pass off as fighting for an open web while blue haired landwhales who can't code for shit has seized the company, shifting focus towards gay marriage, changing offensive file extensions and rejecting offensive addons
eg. this popping out every time you add an extension
>they need to do this in order to provide software for free and still pay the rent, wages etc
ive switched to gmail today /g/, i think its over for me, sooner or later google will get everyone