Now they seem content to profit from it and give nothing back.
This statement is completely false. Red Hat contributes a ton to open source, to thousands of upstream projects, probably more than any other individual company. Software from Red Hat acquisitions has been transitioned from closed to open source. New open source software is often created by Red Hat engineers. Everything Red Hat does is open source and contributed back upstream whenever possible.
To be clear, me saying this is not an endorsement of the RHEL source export changes announced yesterday. I think that sucks. But it doesn't undo everything else Red Hat does.
That's false. The sources are right here, open to the world and open for contribution. What was shut down was the automation to export RHEL source RPMs to the legacy location. The source RPM exports were pretty much useless for contributors and maintainers of RHEL and CentOS. However, they were critical for RHEL rebuilds, which is why people are upset.