Thank you for that link and Thank you to Mozilla for doing those tests. I always suspected something like this but it is good to have it tested and in writing.
My only gripe with the article is this:
All of the car brands on this list except for Tesla, Renault, and Dacia signed on to a list of Consumer Protection Principles from the US automotive industry group ALLIANCE FOR AUTOMOTIVE INNOVATION, INC.
Renault and Dacia aren't available in the US, so there is really no need for them to sign those principles. Which makes Tesla the only one where this is relevant.
I don't know if there are zero Renault in the US but Mozilla themselves say that Renault aren't sold in the US:
source
So it is kind of strange to hold it against them. On the other hand that doesn't seem to be too important because nobody cares about what they signed or not.