BTS requesting to re-perform 2.0 deserves so much appreciation, not cause of their professionalism, but because it was done solely for ARMYS.
If you watched the first performance of 2.0, the outer circle went up instead of the inner circle during verse 1 and it wasn't filmed or seen well. The lift did go down soon after, but it still did not rotate 360° as it was supposed to, so BTS only performed it facing one side.
They initially asked the stage crew if they could do it once more with the lift rotating again, but it wasn't fixed yet. Still, they decided to perform it again, this time facing the crowd on the opposite side.
They didn't perform again just because the lift malfunction made it imperfect, but because armys on the other side couldn't see anything at all.