With the recent agism article, I get the impression that most of the Facebook employees would think Carmack is to old for their "culture".
Not enough of a brogrammer for their standards.
As an engineer at Facebook, I will say that couldn't be further from the truth. Every reaction I've seen has been overwhelmingly positive, full of amazement and excitement at the chance to meet or work with one of our greatest idols.
Come now, your facts clearly have no place in this discussion.
Is there some sort of HN comment guideline that dissuades this sort of garbage?
43 isn't too old. Will you ever say Python creator Guido van Rossum (who is 58 right now) is too old? Figures like them never get old. But will the younger engineers feel pressure when they are talking to someone far more experience far more well known? Certainly.