>>17
Just point out that Donald Knuth, Dennis Ritchie, Brian Kernighan, Rob Pike, Paul Graham, John McCarthy, and dozens of other programmers older, wiser and more accomplished than rms are/were all happy to use ``proprietary'' software if there is no alternative and it is simply better. UNIX and so on were a product, not a charity.
On a related note, they all call(ed) the operating system Linux rather than ``GNU/Linux'', and most of them use(d) open source rather than ``free software''.