After reading the post I don't see how it gives any indication that Mozilla is trying to censor anyone. Mostly it argues for more transparency. It's certainly worth reading.
Blocking is good option to improve individual experience, but a flood of low effort, spammy content from bots makes a very bad first impression on newcomers.
That's grossly exaggerated. I live in western Europe and never once used WhatsApp. There are very occasional frictions, like people being surprised I don't have it. Then when I explain that it's operated by Facebook, they are also surprised and sometimes are willing to quit themselves.
After reading the post I don't see how it gives any indication that Mozilla is trying to censor anyone. Mostly it argues for more transparency. It's certainly worth reading.