I’m beyond offended that anyone thinks it’s okay to decide that some spiritual practices are okay for certain religious groups or ethnicities and not others. It’s racism.
Alongside religious exceptions.
Here it is possible to have both simultaneously.
The intent of the restriction is to keep the harvesting of the peyote plant at a level that hopefully prevents it from going extinct. If everyone was permitted to harvest peyote, it would be available to no one at all very quickly. Native Americans get the exception because the tribal groups that use the plant have a culture of respecting it and being caretakers of it.