the google adwords learning center page on trademarks [google.com] should help you figure out where things may have gone wrong.
google isn't in the business of protecting trademarks, but they respond to complaints.
maybe apple complained (and microsoft and the open group haven't yet).
ianal but maybe if you ask nicely you can get permission from apple to use their trademark - maybe even if you spell it properly in your ad copy, as in "Mac", not "MAC"...