I don't really get this argument. If it's this easy, why doesn't GOG do that for their port? They've done it with other games. I would rather have someone whose job it is to sell games keep track of the compatibility issues instead of having to fine tune things myself.
The same reasons why they don't just release *all* of their games with WINE wrappers: support, and legal rights. It would take them additional time and resources to properly test and troubleshoot the game for OS X, potentially pushing back the release by weeks, or even months. As noted above, there's the likely probability that the game may not work in multiplayer (which I didn't test, since I almost always play games for the single-player experience, or play multiplayer with bots). GOG would have to test and troubleshoot that issue, either with WINE, or the game itself.
So yeah, it's their job to keep track of the compatibility issues. It likely because of compatibility issues that they haven't released an OS X version yet.
Then there's the legalities. The legal troubles surrounding this game are legendary, and I can only imagine what GOG and Night Dive had to go through to even get the Windows rights. How much more trouble would OS X rights entail? Or Linux rights for that matter? It took GOG a full year to figure out how to first get even just a fraction of their library on the Mac - that was a non-trivial effort for games which were pretty clearly legally defined. I think it's safe to assume that for GOG to get full Mac distribution rights would be a decidedly non-trivial effort.
That all being said, if it works in WINE – even if it works well enough with some features not fully working at 100% – I'm not going to let the above get in the way of me enjoying the game.