why all the hate on Macs? If people want to have a Mac version how does that effect PC gamers?
Because, just like console wars and the various other standard tribal conflicts on internet forums, "Mac vs PC" is one of the big classic flamewars. Posting a Mac thread on a typically PC forum is a pretty normal way to draw out trolls and flaming. It's also pretty normal behavior in the comments sections of computer website articles.
(This forum's actually not that bad, compared to others. Like, WoW General, for instance.)
Also, if there ever is a Mac version would PC made mods work on it?
It would depend on the mod. The ones that just need a regular Data folder copy/paste would probably work fine. Although you'd miss out on the more complex mod-arranging & management functions without a Mac version of OBMM/FOMM. Any mods that use more involved stuff (like .omod installs, OBSE, and stuff like that) would be less likely.
(Regular Dragon Age and Torchlight mods, for instance, install ok. The fancier ones, that do odd things and/or need special installers, don't.)