Red Hat had over a billion dollars in revenue last year and it's never stopped growing. Free Red Hat-compatible operating systems did not stop them from making a lot of money.
I think it's extremely common for companies to sit every engineer down during onboarding and say "never touch code with these licenses". Certainly in my experience it is.
This terrifies people for some reason. Basically because they want the freedom to modify open source projects and call it their own without giving back to the project that actually created it.