TL;DR: With Firefox 56, Mozilla combined Firefox Health Report and Telemetry data into a single setting called “technical and interaction data”, which was then enabled by default. This data was then shared with advertising partners on a de-identified or aggregated basis.
You can turn off telemetry, but that doesn’t save Mozilla from ire for pulling this, it’s still a shitty move regardless, it’s an answer to the problem, but it doesn’t justify the problem’s existence or exempt Mozilla from ridicule for it, it’s still a problem and it’s still a crappy move for someone to pull.