He certainly entered his career in France as an entire and by the time he got to Ireland, he was rather old to then be gelded, so I guess the decision was, in view of his already excellent race record, to leave the baubles in place. It's not unheard of to geld late, but it's more risky for a number of reasons, and by then (4 years and over) a colt has pretty much got sex fixed in his mind, anyway, so even taking away the ability won't guarantee taking away the interest in les belles dames!
He clearly seems to have enjoyed the business, though, and a set of jewels wouldn't hamper those efforts. It'll be very interesting to see how the kids shake out - at least they should all be good milers with the paternal line. I like the photo of him - looks really set on what's up next - all focus and intent.