Imagine this scenario. You created something very complicated that you're proud of. You spent a lot of time on it and your integrity and reputation rely on this thing you built.
Little did you know that what you built could be done in a way that is easier and 10x better. The foundation of your reputation is in shambles. What would you do?
I can tell you what I've seen from experience. The very people who tell you that bias doesn't affect them or complain about how politics always trumps technical problems are the very people who will FOLD when the same problem hits them in the face. No one is perfect and there will be a time that this happens to most people... a time when that person will be utterly and completely wrong about something they've advocated for so long.
It's trivial, easy and immature to advertise and complain about the weaknesses in other people. I want to see a blogpost about a programmer coming to terms with their own grave mistakes... their own imperfection.
Once you realize how hard is to do that, then you will know know what to do when this problem infects your work place. First and foremost you must introduce change without hurting peoples' pride. You must be empathetic and take into consideration how other people will feel if you try to pick them apart. If you take steps to do that, people will return the favor in kind. If you attack the scaffolds supporting the reputation of your peers, expect everything that you've built to be attacked as well. Remember. No one is perfect.
The original poster is as responsible for creating a toxic work place as the people he's complaining about. I'd bet he'd react the same way if the tables were turned.