I would strongly bet that the $900 example fare to LED on LH is booked in "K" class. Which earns nothing in UA's MP. And 25% credit in LH's M&M. Moreover, when you go and finally redeem those miles for an award ticket, LH awards have high surcharges as well.

And the reason why I am "defending" it is because it is a trade-off. If there were no BA surcharges, there would be very little BA award inventory available to us. So people now have the option of paying more miles to stick with AA metal and only the minimal fees, when no SAAver awards are available. Or use fewer miles and pay the surcharges. I much prefer this to over at DL, where the 60K Y award to Europe is a rare find, but the 130K one is in total abundance.