They also literally cannot have the same access like everyone else, since they're in a wheelchair. Everything will be different.

That's a different sense of "just like". Not "in the same manner", but "to the same extent".

Would it have been different, if they had everyone take the cargo entrance?

Yes. It's about discrimination and dehumanizing everyday cruelty.

I'm emotionally aligned with you, but the dehumanisation is the default state (e.g. the able are standing and the wheelchair user is below eye level), and all accommodations are a result of society dedicating resources to moving the needle away from that.

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.