Surely the usefulness of what the compiler outputs is at least related to whether it's commercial or not.
If I forked GCC and made a version where the produced binaries would only run on the machine where the compiler ran, and removing that was a subscription...I'd call it a commercial product.
That's something of a technicality. If the output of the compiler isn't useful without paying for something else, it's effectively a commercial compiler.
Sometimes "whataboutism" is just a comparison to something more common that a broader audience can relate to.
Fwiw, I find the canned responses like "appeal to authority", "whataboutism", etc, kind of lazy. I'd prefer you tell me why I'm veering off in your own words.