I think some people in that Twitter thread, pg included, have become so brainwashed by euphemistic phrases like "we agreed to part ways" to cover a firing, that they start to believe their own hype.
A firing can have varying degrees of amicability. It can be a reluctant firing. You can literally say "we're sad to see you go" and mean it. But I think it's still a firing in this case. It is so weird to see people have trouble grasping this.