When you open a freshly installed Firefox on Ubuntu or Windows (that is where I checked) you will have a google cookie set right before the first usage, without any chance of opting out or being asked before.
Yes, anybody can change the startpage, delete all cookies and restart the browser. How many users will do this? And does forcing every user into google surveillance comply with this privacy marketing of mozilla, or is it just a zynical fake campaign?
There should be a startpage explaining what cookies are, describing the difference between temporary and permanent cookies and how these help to track your web usage, and provide one single, visible button to delete all cookies.
After this I should be asked if I would like to help mozilla funding by redirecting me to a google web search which will set a permanent cookie.