You phrased it in context like you thought using a Mac was preventing you from using a mouse with a middle button, especially when it was right after the section complaining about the Magic Mouse.
Middle-click paste is one of X's many usability fails, especially since it's a convention adopted by no other UI. All the rest assume a max of 2 essential buttons.
Command-C and Command-V are just so much better. Learn to love them.
