I think they have a point. Mozilla could easily ask for consent from users but they chose not to. Hiding behind sophistry about whether this is technically "tracking" doesn't really change that.
If it is just an alternate more private attribution method, why is there such a "need" to ship this over the concerns of users? Why does it matter if more users use it (from the outset)?
So, as far as points go, it kind of makes sense. Maybe, someone could argue whether this is the right vehicle for this but arguments for it also come off as hollow.
https://www.zdnet.com/article/how-does-adblock-plus-make-money/
We also have to remember that it is not unusual for a service which purports to be about blocking ads to have an "acceptable ads" program of ads they choose to whitelist (which they then make money from).
So, if someone sees Mozilla, a company known for having troubles with making money, behaving like this, what are they going to think?
https://brave.com/blog/intro-to-brave-ads/
Another one is the Brave Browser which purports to be "private" while doing all this surveillance.
https://en.wikipedia.org/wiki/Brendan_Eich
Brave was created by Brendan Eich, who also co-founded Mozilla.