It's because people looked at a line of a diff without looking at the actual context.
It's like finding the line in a diff where someone deleted a call to "check password" and concluding that this means the service is no longer verifying passwords.

https://blog.mozilla.org/en/firefox/update-on-terms-of-use/

https://www.mozilla.org/en-US/privacy/faq/

We never sell your personal data. Unlike other big tech companies that collect and profit off your personal information, we’re built with privacy as the default. We don’t know your age, gender, precise location, or other information Big Tech collects and profits from.

Basically, they consolidated and clarified their data privacy policies to be legally accurate. People took a content change to be a policy change on the assumption that you can't just delete words in one place and put new ones somewhere else.