Organ donation and body donation are two different things. If you donate organs, only the organs are used to put in other people. Body donation is less well regulated, and there’s definitely some sketchy businesses involved, but if you go through a university or medical school, you’ll be good.

It’s also not illegal for you. Blood banks used to not accept blood from men who have sex with men, but that has been changed. Even at the time of that outdated article you linked, organs were fair game as seen in the correction at the bottom.