This argument has been had thousands of times across thousands of forums and mailing lists in the preceding decades and we're unlikely to settle it here on the N + 1th iteration, but the short version of my own argument is that the entire point of Free Software is to allow end users to modify the software in the ways it serves them best. That's how it got started in the first place (see the origin story about Stallman and the Printer).
Stallman's insistence that gcc needed to be deliberately made worse to keep evil things from happening ran completely counter to his own supposed raison d'etre. Which you could maybe defend if it had actually worked, but it didn't: it just made everyone pack up and leave for LLVM instead, which easily could've been predicted and reduced gcc's leverage over the software ecosystem. So it was user-hostile, anti-freedom behavior for no benefit.
> Which you could maybe defend if it had actually worked
It did work, though, for 15 years or so. Maybe that was or wasn't enough to be worth it, I don't know.
I have no idea what you think "gcc's leverage" would be if it were a useless GPL'd core whose only actively updated front and back ends are proprietary. Turning gcc into Android would be no victory for software freedom.
> the entire point of Free Software is to allow end users to modify the software in the ways it serves them best
Yes?
> completely counter to his own supposed raison d'etre
I can't follow your argument. You said yourself, that his point is the freedom of the *end user*, not the compiler vendor. He has no leverage on the random middle man between him and the end user other than adjusting his release conditions (aka. license).