http://www.gbadev.org/ is a website that is all about GBA development. None of the ROMs on there were made by companies or copywrited, and the emulators on the site are freeware.
ROMs and emulation CAN be legal, but in most cases it is not. I think the rule should be revised to only stop talking about/posting links to/uploading files of copywritten ROMs/emulators instead of all ROMs/emulators because there are many cool ROMs that are perfectly legal to have, keep, and use.