Well he wasn't "removed". Biden himself stepped down when it became obvious to everyone who watched the debate that he's incapable of fulfilling another term as President and the pressure became too much for him to ignore. He finally did the right thing, which he should have done much earlier. Nancy Pelosi is probably the one who put the most pressure on him and masterminded installing Kamala, which may have been a genius political move. I think there was still plenty of time to do a condensed primary but the looming threat of The Rapist made it important to minimize any possible hiccups. Kamala wasn't popular at all at that moment but she's been phenomenal on the campaign trail and her choice of Walz was a great move. Regarding West or Stein do you really believe Republicans wouldn't do the same thing? Trump is a huge threat so anything that minimizes his chance of getting elected are game, IMO.
