If you accept that it takes a lot of effort to produce what Red Hat produces and you accept that you cannot buy food with a list of your open source contributions, then the people who work for Red Hat need to be compensated in some way.
If your answer to this is that there is a big, distributed pool of people willing to do this work instead of Red Hat then you don’t believe that Red Hat adds value. But the question remains: who compensates those people?
And this big distributed pool of people ready to do free work definitely doesn’t exist already. Well, it does, but it’s just Redhat. And they are rightfully changing that.
It could be the companies they work for (like is done with the Linux Kernel), but that doesn’t exist and starting it is a pretty big undertaking.
At the end of the day the comment in the post about the anger coming from people who “do not want to pay for the time, effort and resources going into RHEL or those who want to repackage it for their own profit” rings pretty true.