Maximum wrongness on your part.
This is the original text that everyone flipped out about (OP: "WHY DO YOU NEED MY DATA TO MAKE FIREFOX WORK???"):
When you upload or input information through Firefox, you hereby grant us a nonexclusive, royalty-free, worldwide license to use that information to help you navigate, experience, and interact with online content as you indicate with your use of Firefox.
It has since been changed to:
You give Mozilla the rights necessary to operate Firefox. This includes processing your data as we describe in the Firefox Privacy Notice. It also includes a nonexclusive, royalty-free, worldwide license for the purpose of doing as you request with the content you input in Firefox. This does not give Mozilla any ownership in that content.
Use. When you input a url, that information is used to resolve an IP then fetch a webpage. You're granting a right to complete tasks you assign using information you input. They have permission to send your post content to a server, but they don't own that content. This should be very obvious in the revised text.