Simple version. Wine runs Windows programs without a Windows Kernel of any sort.
Wine provides an API to match the userland API of Windows, but under the hood it does not, and never has had the internal Kernel mode API to simulate the inner workings of Windows. That is it only simulates the way the Windows kernel looks like it behaves, not the way it actually behaves.
Moreover kernel mode drivers often contain code which is restricted by the CPU in userland. This can include CPU Opcodes for hardware access. For wine to allow this code to run it would need to either:
- Emulate a CPU. This is both slower and a lot of work. It usually needs very specialist tools like qemu
- Run the Windows driver (somehow) inside the Linux kernel. Doing this safely would be almost impossible.
Since Wine does neither of these things, it's just not possible for them to provide this feature.
Having played LoL myself, I'm not surprised Riot have taken this action. The last time I played, some game modes (particularly "all random") had excessive bot players screwing the games up for everyone.
Locking it down in the most tricky way possible is designed to make it as difficult as possible to run LoL on another platform. It is designed make it only interface with windows so it won't interface with bots.