I think this piece of advice is pretty invaluable and I suspect that you might have the wrong impression of what this means.

I take it as a call to learn how to communicate your thoughts effectively as well as understand what motivates other people. I worked in a technical consulting company and the most effective people were the ones that could sell their ideas to customers/ within our organization as well as deliver technically. I don't think it's enough to purely be a technical person or a good communicator, developing both skills are pretty crucial to getting ahead as well as work effectively in teams.

The working out part is definitely a flex, but it something that most people should do but don't.