I know it's been said that they generally do have a bit more of a problem booking younger, male celebs so maybe that came into it
It's always struck me as a bit bizarre that they only really ever get one 20-something male per season and only two under 25s in the past 10 seasons (HRVY & Jonnie) so it wouldn't shock me if that was true but I can't see why getting younger men is a lot difficult than younger women. Especially if looking for a career boost. Other versions don't seem to struggle.