Google does not control Mozilla. For a few years, Mozilla had a contract with Yahoo as the default search engine, but switched back to Google for complicated reasons. In any case, Google isn't the only option for Mozilla, and there are other companies who would happily pay just as much money.
Mozilla has opposed Google many times, and is doing so again in the very link you are commenting on. Mozilla is not completely free from economic realities, but we are definitely not controlled by Google.
(Disclaimer: I'm working for Mozilla as an SRE.)