He is talking about the difference in difficulty of local vs remote, not the difficulty of managing full stop.

And he is right, managing remotely is a minimal change. I've been managing and working with people remotely for years, as has everyone who deals with coworkers not in the same office as they are.

It doesn't matter to me if they are in an office in another country or in their jammies at home in that same country, they are thousands of miles away from me.