It's simply intractable to add up everyone's advantages and disadvantages

Sure.

    it's the wrong path to focus on group attributes/trends when you start talking about individuals.

Absolute nonsense. If a particular school had a 30% graduation rate while every other school in the state averaged 80%, would you say, "Wait a minute! It's the wrong path to talk about this school in particular. These are individual kids..."

As you say, every individual human being certainly is more than the some of their labels. But when gross inequalities between groups emerge, it's lunacy to suggest there are no greater group-wide forces at work on scales greater than the individual.

    Would you tell Michael Jordan to check his privilege if he told a group of average white male nerds to reflect on theirs?

Is Michael Jordan a group of people? Unless there's a clone army of Michael Jordans out there that I don't know about, this theoretical question is bizarre and irrelevant to anything anybody is talking about.

I'm not even sure what you're getting at here. He is a part of some privileged groups (rich people, people with one-in-a-million athletic ability, men) and not others.

    I could clamor for tall rich sportsmen to "send the
    elevator down for me". That it's their responsibility
    and so on.

Michael Jordan can't make you a rich, tall sportsman. That's not... physically possible. However, the author of the original article suggested that we help others achieve careers in our industry. Now that certainly does seem possible, doesn't it? Hardly even seems controversial, if you ask me.