Queue times are currently short for those particular instances for the following reasons:

Expert: Everyone wants Poetics. These dungeons are also involved in the Zodiac Quest.
High Level: These dungeons - all of them - are involved in the Zodiac Quest right now.
Syrcus: There are still people gearing up alts and collecting Sand and Oils.

Also, I believe it's been observed before that Melee DPS tends to have lower queue times than Ranged DPS because the Duty Finder tries to pair up a 4 man as Tank/Healer/Ranged/Melee. Even though Ninja is a thing, apparently there are still fewer melee players around than there are ranged.