I think this advice is only necessary if you end up working for one of those companies that expects you to "show dedication" and "take ownership" and "be a team player" and "get into the company culture", i.e. work constant overtime. If you work a normal, sustainable, healthy, adult 40-hours-a-week, in your own town[1] there is still plenty of time to get some learning done at home.

Really, you should be learning on your own dime. Because if you're learning on someone elses dime, you're probably not actually learning correctly. You're pulled in two different directions, that of you trying to learn something and that of your boss wanting something productive out of you.

But if you just jump off the cliff already, I think you'd be surprised just how much you can learn in a very short period of time when you don't have to contend with common office distractions.

[1] I am always amazed at the throng of traffic every morning, city folk commuting to the suburbs and suburban folk commuting to the city. Just swap jobs already! Hell, why do so many people put up with taking jobs that require them to go to an office? It's so incredibly unnecessary for so many different types of work, yet people still do it. Trained monkeys.