I can't blame you. They are rather arbitrary
I would understand if they dumped them for a more sensible system, especially in a new interesting setting.
But the dumb schools just feel like DnD to me at this point.
Wizards without their schools just wouldn't feel right, in a standard (if there is such a thing...) DnD setting.
I think that is possibly one of the great problems/joys with DnD. It is a horrible mish-mash of every conceivable fantasy setting and trope, monsters from every possible mythology and setting.
And none of it was planned in a cohesive way...
Some settings are better at it than others, but it is a beautiful mess that just "feels" like DnD.
I think i have some difficulty looking at my own sacred cows objectively. Some thing i just like because i like them