How does this violate the GDPR? It increases privacy and stops advertisers tracking everything you do. This seems to be a good thing.
Advertisers have always been interested in where their ads are seen and whether they convert to purchases. A common example is vouchers, which will tell the advertiser exactly this (10p off, customer redeems, store returns to advertiser, advertiser knows where you got the voucher from/where you saw the advert, where you bought the product - exactly what Firefox is trying to tell them)
Firefox creates a report based on what the website asks, but does not give the result to the website. Instead, Firefox encrypts the report and anonymously submits it using the Distributed Aggregation Protocol (DAP) to an “aggregation service”.
Mozilla can’t send user data to an “aggregation service” without explicit consent, no matter how much propaganda they use to explain it.
But it’s OK to send more - and probably PII - tracking data directly to the website without consent?
Also no. But 2 wrongs don’t make a right.
You are speaking like there are only two alternatives and none of them involves following the law.