It takes two.
If accurate and true, there is an obvious conflict between the two of you. John perhaps didn't listen to your point of view enough and in the reverse you didn't respect his view and role in the company.
His success was your success and it would seem you both failed as a result of the conflict.
Tech is full of difficult personality and ego. It's multicultural and communication challenges and cultural differences are common are often misinterpreted.
At the end of the day though, many of us just want compassion and respect in our roles, to be valued and heard.
All said, feel in this described circumstance that perhaps the initial folly was all indeed John's. He held the power after all to make the right start.