They don't have an open source kernel. You can't recompile the kernel or build your own device drivers. I'm not sure what you mean by "learning about computers", but I personally find being able to peek into the kernel source code to be more educational than anything in the mac ecosystem.
The hardware here is incredible, but it's crippled by not adequately supporting Linux, BSD, or any other properly open source kernel you can compile and install yourself. A good learning environment doesn't put up immovable barriers like "you need a kernel signed by apple", it lets you push away barriers when you're ready, like "Are you sure you want to turn off secureboot, or install your own secureboot keys"
The hardware here is incredible, but it's crippled by not adequately supporting Linux, BSD, or any other properly open source kernel you can compile and install yourself. A good learning environment doesn't put up immovable barriers like "you need a kernel signed by apple", it lets you push away barriers when you're ready, like "Are you sure you want to turn off secureboot, or install your own secureboot keys"