TLDR: The Mozilla Corporation claims to run on user donations, while official records prove they actually make so much money from web search defaults that if all user donations stopped, they’d be fine. The Mozilla Corporation spends it’s money on political activism companies or vague and shadowy companies that very little public information can be found on.
2021 is the column on the left, 2020 is the column on the right. The author is correct (factually; conclusionally I’m less sure.)