Comment by pjmlp
My mistake, as I assumed they took the same decision as jython and IronPython.
https://jython.readthedocs.io/en/latest/Concurrency/#no-glob...
https://wiki.python.org/moin/IronPython
The difference between JVM, CLR and C in regards to parallel and concurrent code is that they are built for those kind of workloads, and have a memory model proper, hence not needing a GIL.
I think they would have to here, to support native modules. Jython (and I believe IronPython, but don't quote me) does not support native CPython modules. CPython modules explicitly control the GIL, so if they are supported (as they are here), you can't really leave the GIL out without exposing potential thread safety issues.