a person can be an open source supporter while using proprietary apps. Just because a person is a Ford aficionado doesn't restrict him to Ford products when something better suited to a job is available; a dump truck over a Mustang, for example.
"Yes there are some softwares that aren't closed but they aren't Mac or Apple."
See the OpenOffice.org download list here:
http://download.openoffice.org/other.html#en-USor The Gimp:
http://www.gimp.org/downloads/or Firefox:
http://www.mozilla.com/en-US/firefox/all.htmlIn all three cases of these open source products, note the options to download for Mac. Not enough apps for you? Then see
http://www.opensourcemac.org/I'd post more examples but I sprained my finger scrolling down that last one.