Why do the Dravidians not get Redemption?

Most of the time, Redemption isn't given to archer civilizations (Britons, Mayans, Chinese, etc.) so that Mangonels can counter them (Italians and Saracens are exceptions, but they have a weak early game on land maps). However, in the case of the Dravidians, they only get generic Xbows and Elephant Archers are very hard to mass in 1v1's. Their Skirmishers might fire faster, but they're still very weak to cavalry, while the Dravidians have a terrible Stable and thus can't really dive onto enemy Mangonels. Mangonel pushes are hard for the Dravidians to handle, and Knight raids give them a lot of grief.

This makes me wonder why the Dravidians don't get Redemption at the Monastery. They also miss Fervor, Heresy and Illumination, but it's mainly Redemption that sticks out for me. Without it, enemy siege units can't be converted, so the Dravidians can't use Monks as a counter to Mangonels.

Would giving Redemption to the Dravidians make them too good? I personally don't think so, as Mangonels right now beat pretty much anything the Dravidians can field in Castle Age due to their terrible cavalry.

EDIT: As u/Mankaur pointed out, nearly every civilization has either +2 Knights, Redemption Monks, Eagle Warriors, or a fast UU to deal with Mangonels in Castle Age (i.e. Woad Raiders, Shrivamsha Riders). Dravidians, however, don't have these options, making them exceptionally vulnerable to Mangonels in Castle Age. Some have said that Urumi Swordsman are the answer, but I don't think that's true, as Urumi Swordsmen are squishy, require a Castle, and don't compare to Knights as a counter to siege (Knights are tougher and faster). Additionally, while others have said the Dravidians could just make their own Mangonels as a counter, that's not usually a good idea. Since the Dravidians cannot raid their enemy's economy with cavalry, while the enemy can raid theirs, Dravidians cannot afford losses of Mangonels while their enemy usually can.