The problem is more that they actually do want to sell user data (albeit anonymized and/or aggregated), and they want to present themselves as a privacy-favoring alternative.
They literally say:
> Mozilla doesn’t sell data about you (in the way that most people think about “selling data“), and we don’t buy data about you. Since we strive for transparency, and the LEGAL definition of “sale of data“ is extremely broad in some places, we’ve had to step back from making the definitive statements you know and love. We still put a lot of work into making sure that the data that we share with our partners (which we need to do to make Firefox commercially viable) is stripped of any identifying information, or shared only in the aggregate, or is put through our privacy preserving technologies (like OHTTP).
Sharing data with partners and getting money in return (that's what "to make Firefox commercially viable" means) is selling user data. They want to change the definition of selling data to exclude what they want to do, but they don't get to decide what the meaning of words is.
So they're not as privacy-friendly as they want to appear, and that's a difficult position, and that's why this policy allows them more access to data than a naive reading would indicate.
They literally say:
> Mozilla doesn’t sell data about you (in the way that most people think about “selling data“), and we don’t buy data about you. Since we strive for transparency, and the LEGAL definition of “sale of data“ is extremely broad in some places, we’ve had to step back from making the definitive statements you know and love. We still put a lot of work into making sure that the data that we share with our partners (which we need to do to make Firefox commercially viable) is stripped of any identifying information, or shared only in the aggregate, or is put through our privacy preserving technologies (like OHTTP).
Sharing data with partners and getting money in return (that's what "to make Firefox commercially viable" means) is selling user data. They want to change the definition of selling data to exclude what they want to do, but they don't get to decide what the meaning of words is.
So they're not as privacy-friendly as they want to appear, and that's a difficult position, and that's why this policy allows them more access to data than a naive reading would indicate.