I think it's bullshit advice. It sounds like the remnants of a dying mysogynist corporate culture where appearances mattered more than substance.

Working people are smarter now than they were at any point in history. They're just pretending to be stupid in order to fit into existing social power structures. But they can't continue to pretend forever.

The notion of a working class which is smarter and better informed than the ruling class is a new situation which did not exist before and it's going to be interesting to see how it unravels as the intelligence and ambition gap widens.

We are currently in a transition period; a dark age for progress. Smart people are being suppressed and coerced by a powerful class of ruling idiots who are using any means necessary to maintain a highly unstable status quo which is the enemy of progress itself.