That old root tutorial is obsolete.
You used to be able to root with only a remote connection using the Android SDK tools which are available for Mac. However the exploit in the phone's software that allowed this was patched out in an update.
The only way to root now is to flash properly modified software to the phone using the Odin flash software that Samsung let loose into the wild.
Unfortunately, Odin only works on Windows.
It does work on a Mac if you run it under Bootcamp or a virtual machine like Virtual Box, Parallels, or VMWare.