I'm late and this will get buried, but this really speaks to the difference between the open source / ESR / OSI ideology and the free software / RMS / GNU ideology.
Open source ideology says it is better because it produces better software. If MacOS X was closed source and better it serves as a repudiation of that ideology.
Free software ideology says it is better because denying users any of the four freedoms is an immoral act. If MacOS X was proprietary software and better, it would still be immoral to deny users their freedoms; the ideology is not impacted.