Could you give some examples of things they do that you disagree with? I can't really think of any controversial non-firefox things they've done.
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).