Why is this an irrational viewpoint? Sure, someone who has an advanced degree is unlikely to be dumb. But as any remotely educated person should know, it does not follow that someone who does not have an advanced degree is not smart.
I think the obsession with advanced degrees is fascinating though. Do people really believe that getting an advanced degree will make one a more productive web developer? Are the years spent getting that advanced degree remotely comparable to years of meaningful industry experience? Or comparable to using the countless online resources to educate oneself in topics that are directly applicable to web development?? Hint: no.
[1] "Brains don’t matter as much as resilience in your first couple of years as a startup. I borrowed a lot of money to put myself through one undergraduate and two masters programs so, yes, it hurts to write that."