Well, the prevailing wisdom is that these accommodations improve fairness. To confront that way of seeing things is an uphill battle in the current intellectual environment.

I know it's a losing battle. The way I see it is if you're not going to test performance under pressure, give everyone as much time as they want (within reason). If you want a fair stress test, don't discriminate and give special privileges.

Well, they don't see it as privileges, but accommodations for a health condition. The measurement method needs to be adjusted when the health condition is present, to make the same kind of determination about the acquired knowledge. Experts have likely written expert publications about this being like this and hence it is The Science.