Deno is something in javascript-land that just popped up (I'm not sure what exactly what it is, since I haven't keep up about JS ecosystem since friday and everything has changed), so yeah it's a joke that they require 5 years of experience in it.
IIRC Deno is a new JS runtime built by the creator of Node and written in Rust that pledges to resolve some of the hairier issues with Node. It’s actually one of the JS projects I’m most looking forward to maturing.
Unless they're trying to catch a time-traveler.