

Yes, because the definition of “sell data” varies by jurisdiction, and they can’t guarantee that their usage of ads (eg the default sites that appear on the new tab page) does not fall under the definition of “sell data” in some jurisdictions. In particular, California’s CCPA is pretty strict and some use cases that aren’t actually selling data still fall under its definition of “sell data”.
That’s not what they actually did, though. They revised the wording to clarify:
For example, if you type something into the address bar, they need to have the permission to take your content (whatever you’ve typed) and send it to a third party (a search engine) to get autocompletion results.
Here’s the blog post that clarifies the changes: https://blog.mozilla.org/en/products/firefox/update-on-terms-of-use/