I think Damore's fatal flaw was naivety. He thought his opinions would lead to a better Google and he thought Google wanted to hear arguments that would lead to an improved Google. He clearly lacked the awareness to realize he was not speaking to a receptive audience to the ideas he had. And he wrote something that lacked the... emotional awareness... to understand where the opposing view came from or how his memo would be received.
You can furthermore see that naivety in how quickly he ended up accepting offers and olive branches from alt-right personalities. It seemed like he wasn't aware who he ended up 'siding' with.
You can furthermore see that naivety in how quickly he ended up accepting offers and olive branches from alt-right personalities. It seemed like he wasn't aware who he ended up 'siding' with.