Sour grapes and misinformation. The reason to break up with Firefox (and especially Chrome and Safari) is that they are browsers which believe and are designed in a way where the end user does not have control. The end user is to be protected from themselves by removing control. It started in version 37 with Firefox, when they made it so you can no longer edit or add extensions without first getting approval from Mozilla. It's only become more like Safari and Chrome in the years since.

Don't break up with Firefox because they mentioned a way to donate you don't like. Break up with them because they're actively shipping browsers that are user hostile. Just like Apple and Google.