"Have they not heard of Macs?" Next to the plug-in DL link, it says "(PC Only)" so maybe not. Do the same plug-ins usually work on both platforms? It does seem a bit of an odd choice to use the self-extractors, even for the PC. All they're doing is unzipping the files and folks are more leery of DLing an .exe than a .zip - who knows?

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken