Why are Camel Archers a go-to strat in 1v1s for Berbers, but not Mangudai for Mongols? It makes no sense.

Over and over in top level matches, I see people going straight for camel archers with the berbers, and I just don't get it.

Here's a side-by-side stat comparison between Camel Archer and Mangudai to work with:

So you can see mangudai cost sliiightly more and take 25% more time to build. They also have 1 less pierce armor and deal 1 less damage. But they attack so much faster that it just overrides this entirely! Camel Archers have a reload time of 2, while Mangudai have a reload time of 1.68 before you apply the Mongol 25% faster shooting bonus. They fire a lot faster. They are the stronger unit.

So why are people always going straight for the UU as Berbers, as if they were spanish, but never do you see this done with Mongols? People don't just go straight for a castle asap and then depend on their UU entirely as Mongols, not til late castle / imp. But with berbs they go straight for the Camel Archer immediately, mining stone in feudal to get the castle ASAP.

What is with this??