I'd rather buy a browser as a company's primary product, not donate to Mozilla which makes a browser and does many other things, many of which I disagree with and would rather not fund.
https://jolt.law.harvard.edu/digest/mozilla-announces-resign...
https://wiki.mozilla.org/Speaker_Series#Monday_Oct_1.2C_2018...
https://twitter.com/datasociety/status/1093227579723730946
I could go on forever with Mozilla's connections to organizations promoting and facilitating politically motivated censorship.
Because I think when people ask about Mozilla controversies they're thinking about situations in which Mozilla has "broken character" by e.g. risking users' privacy, not activism that is absolutely in line with Mozilla's stated goals (whether you personally agree with them and their interpretation thereof or not).