This is mostly true, but there's nuance to that which I believe doesn't make Stream a "fully GPL compliant target for RHEL sources".
Some sources do not hit Stream in a way that makes it possible to rebuild a release of RHEL verbatim, and devs can and have reported issues with compiling against Stream for deployment to RHEL, especially for the latest versions, where Stream and RHEL are diverged for a time.
Some sources do not hit Stream in a way that makes it possible to rebuild a release of RHEL verbatim, and devs can and have reported issues with compiling against Stream for deployment to RHEL, especially for the latest versions, where Stream and RHEL are diverged for a time.