Red Hat, which is a public company (which did yield a significant "going public benefit" to their founders) and is profiting from the work of countless unpaid volunteers and enthusiasts, is a very clever, but deeply unethical entity.
Why exactly is this "deeply unethical"? The authors of the code they are selling licensed it explicitly in a way that allows such use. If the original authors were anti-profit, they would have put one of those obnoxious no-commerce clauses in their licenses.

People who publish code under the GPL aren't bothered with other people commercializing their code, because they know that the purpose of the GPL is to ensure that no other entity can further restrict the right of the recipient of that code to modify and redistribute it. Because of this, third parties will usually have very little commercial leverage with GPL code, but nobody is stopping them from trying. The more copies of Red Hat's distribution are sold, the wider the audience for my software is, and the more patches get sent in to improve it for my own uses. Sounds like a damn good deal to me.