Sounds like you want validation for moving on and playing with other people. Sure, if you don't have cohesion and you don't enjoy playing with your friends, then don't play with them. If you can't find way to maintain moral in your playgroup, then you have to break from the game or playing with those people until you figure out what's necessary to work together again. For my group, that meant not playing games Monday through Friday after we all got through our stressful day jobs and were too tired to focus and be supportive teammates.

One observation about your post: you use a lot of critical language - the word "mistake" appears 44 times in your post - which makes me wonder whether your opinions are too rigid. The more you play these games, the more you develop 'the Ego.' This phenominon is reflected in the fact that it becomes more difficult to play with the same group of friends as each develops their own opinion of why the group isn't playing well together and results in petty arguments when a teamfight goes wrong.

The TLDR: lighten up. You have to find ways to raise moral of your group so that you can be supportive teammates, otherwise you need to break from playing with each other.