It is not that GNU tools were removed. It is more like GNU tools were not added. There is no reason too. Mac provides its own POSIX compliant tools. If you prefer GNU tools, well there is GNU/Linux. If you don't mind more traditional POSIX compliant tools, then macOS is a good option, as are FreeBSD, OpenBSD, etc.
It is not that GNU tools were removed. It is more like GNU tools were not added. There is no reason too. Mac provides its own POSIX compliant tools. If you prefer GNU tools, well there is GNU/Linux. If you don't mind more traditional POSIX compliant tools, then macOS is a good option, as are FreeBSD, OpenBSD, etc.