See, you do understand. It is evenly distributed.

LSD's in functionality make it more difficult to spin one tire without spinning the other. Even if you do break a tire loose with LSD, more power is being distributed to the other tire. It takes more power to break a tire loose with an LSD, so that additional effort is also given to the other tire.

As I said, with an open diff the power is actually still evenly distributed. However, because its so easy to break one tire loose, thats the same effort the other tire gets, but is not enough power to do anything.

Think about a vehicle with an open differential but it has traction control. TC applies brakes to the spinning tire(resistance). What does that do? Makes it more difficult to spin it. Because it now takes more effort to spin the tire(because TC applies brakes to that wheel), that same amount of effort is also given to the other tire.

Locking diffs shouldn't need explanation.