Mozilla was an investor in Cliqz, so it's not precisely a full-on third party. And the data was (at least, according to the article) well anonymized.

I can see why Moz would want to try and keep up with the user advantages of collecting this information -- catching malicious URLs, etc -- but even if it's just appearance-wise, they've lost a bit of trust here.

Frankly I think they should have two distributions of Firefox, one that's bells-and-whistles for the best user experience, and another that takes a more aggressive pro-privacy stance. This can be little more than the set of preinstalled extensions + default config.