Who said anything about there not being any GCMs/ISOs?
Why don't you just tell him what he wants to know instead of taking him on a long thread ride leading to a closed topic.
"Emulators" are supposed to be for informational purposes and in that process the obvious thing to do would be to test ripped gamecube games that you own already.
No one wants anyone talking about how to get gamecube files on this or most any forum online so do not ask.
Downloading the dolphin emulator is free and therefore they do not owe you anything and do not provide any original game content for you to use with the emulator (Nintendo owns Nintendo games not the dolphin team). Find a way to get a game on your pc and try it out... that's all i can say.