Its about people wanting to hire themselves. It's a cognitive bias we all suffer from. Being completely unaware of it and purity testing others based on your own experience, is: to be precise, a lack of experience in realising that other people can be just as good as you but took a completely different path to get there.

Nah, I bet they suck, why can't they do what I've already done?

Yes, this is the bias we are looking for. If you can't quit vim, don't know how your frontend communicates with your backend, can't type on a regular qwerty keyboard without looking at letters, or navigate UI without mouse, never used a debugger, don't know how to check if it was DNS, can't write a spec for a feature, after talking to stakeholders (and defend it's priority on their behalf), or don't know how to open dev tools in your browser - you are not ready to herd the cats yet, they will herd you off the cliff instead. And that's okay, you'll get there someday.