If Jago is looking to make his DP safe, why would he cancel into Shadow Laser Sword (which can be Shadow Countered) when he can cancel into Shadow Endokuken?

Shadow Laser Sword is safe on block (except if your opponent can shadow counter), while shadow Endokuken is actually strictly punishable on block by most characters, and also won't connect if your DP hits. Most people don't try to punish a point blank shadow Endokuken, but it's somewhere in the -6 to -7 range. You just have to push your punish button really early, because there isn't much block stun on the last hit.