I am unsure as to whether you are scorning or agreeing with the author. You pointed out that a) this is tongue in cheek and b) seem to agree with the fact that founders shouldn't be scorning anyone not following in their footsteps.

Why can't the author make a generalization about startup founders based on his experiences? We all have stereotypes about other races, nationalities, people with a certain 'look'. Of course there are many shades of gray in between. That doesn't preclude us from associating certain character traits with someone before we've ever spoken with them because of how they look or where they are from.