You were asserting that the majority of programmers think Linux == UNIX and have never tried to write a portable application.
Thst is clearly false as the majority of programmers probably confuse Mac OS X for UNIX and most modern unix-like software is portable to at least Linux, Mac OS X, and FreeBSD. Portable is more general than "portable across every UNIX that has existed."
Increasing the specificity of your argument mid-way to avoid the incorrectness of your initial general argument isn't very genuine.
But yes, your revised second statement is probably correct: most UNIX programmers have never tried writing portable code across "DG/UX, Solaris, HP-UX, Aix, FreeBSD, Red-Hat, Debian" exactly because there is no practical reason for it.
