I’ll try to give better context since you’re coming in blind.

As in many sports, “fired” isn’t generally the term used when athletes are dropped from teams, but it’s true that he likely would have preferred to continue racing at least for his current team, Sauber.

Bottas is generally very well liked, and there’s no indication that there was a personality conflict between himself and Sauber. Unfortunately, this is a very competitive sport and Bottas is nearing the natural end of his career. He has been blisteringly fast before, but was never a serious world championship contender, and the team he’s with have decided to move on with other drivers.

Prior to racing with Sauber, he was a reliable and quick #2 driver at powerhouse Mercedes, cementing them as one of the most dominant teams of all time, and helping them to a string of championships. During this time, one of their fiercest rivals was Red Bull. Red Bull has their own pipeline of talented drivers, and while they likely respect Bottas’ skill, it’s unlikely that they’re interested in hiring aging talent that is firmly associated with their rivals.

If I could use a strained example, it’s a bit like saying that Steve Ballmer of Microsoft wouldn’t get a job at Apple because Steve Jobs didn’t like him. It may be true, but Jobs has no control over Ballmer at Microsoft and couldn’t fire him in any case.