Radio 1 is a ****ing joke in general.
They don't use Paloma Faith for the same reason, yet she still charts high and is one of the biggest stars in the UK right now.
But they do use Lily Allen, who's actually not that 'young' too (if we're judging her by their age rules) so they only embarrass themselves by doing this tbh.
They left Hurts off their playlists too during the entire Exile era, probably because they weren't 'new' anymore.
Like I said already, they're a joke.