It’s an observation, not a prescription. Is it “discriminatory” to suggest that gymnastics is a young person’s game?
edit:
just to clarify, it would be an observation to say "Most Mathematicians produce their best work when they're young" or "Most gymnasts who make it to the olympics are young"
But to say that X is a young mans game is inherently discriminatory.
A view held by some seems to be that since even the empirical observation may "perpetuate" the situation, stating it is "problematic" in itself, but I don't suppose this is what you mean here.