On RHEL 7 (and earlier) `/usr/bin/python` must be the Python 2 the system shipped with or your break `yum` and other admin tools. When people try to install their own python by doing a `make install` as root, `yum` breaks and it's hard to recover the system.
What the article is saying is that RHEL 8 addresses this by having a platform python that the system tools use. So RHEL 8 tools will not use /usr/bin/python