redhat does have some documentation on how to work around docker issue, they understand that they are the cause of the issue, sadly it extends to all RHEL derivative distributions.
most searches will tell you to disable firewalld and use iptables, but you can definitely make the rules manually and still have success. as for the political motivations, you could very well be right, but I don’t really follow all that enough to comment.
as to the comment about iptables being present, firewalld overrides it if it’s in an active state. if you want to use iptables, you must deactivate firewalld, but again, you can create the rules manually if you love the ease of firewalld.