Closest I know is a Nintendo fanboy who is turning 36 in a couple of days. But he's not quite like you describe.
He absolutely thinks Nintendo can do no wrong, but he does dabble in other platforms too. I game with him remote on PC like once a week or so.
Arguing on CE be all like:
https://youtu.be/JpRKrs67lOs?si=kPGA2RCKVHTdbVrJ