"the company looked at the history of social media over the past decade and didn’t like what it saw… existing companies that are only model motivated by profit and just insane user growth, and are willing to tolerate and amplify really toxic content because it looks like engagement… "
You can donate to Mozilla, and I do. https://donate.mozilla.org/en-GB/
A lot of people will have to donate a lot to equal the amount they are getting from Google though, and if Google pulls that money I feel that Firefox would end before people donate enough to make up the shortfall.
Money donated to Mozilla goes o ly ti the foundation. The money paid by Google goes to the Mozilla Corp (Firefox).