My old company had a no a**holes policy. They were burned one time too many by smart-ish jerks whose ability to stop a project with pointless squabbling, and rudeness out weighed their ability to complete a project.

The examples given of technologies to avoid are actually in the language to reduce code complexity and do a fantastic job of that. This won't make the code more readable for junior devs it will model the bad habits of the previous generation of programmers for the new generation. More likely this is a policy put in place by a manager who wants to micromanage developers and does not want to keep up with the new language features.