Would it have been different, if they had everyone take the cargo entrance?
It may not be sufficient, and we should criticise when it isn't sufficient, but we must in practical terms also accept tradeoffs in a scarcity economy. In the worst case, some of those tradeoffs accommodate one disability over another disability.
If the dean had a swanky office and the wheelchair kid must roll past the bins, then the school made the wrong choice. But if it's a ramp at the front or textbooks, then we must think a bit harder.