It's like saying that the Mac OS sucks for games. In reality the OS is fine, it's just that developers won't make as much money for their Mac version so they put far less time and effort into making them function as well as they do on Windows. Only a few companies, Blizzard in particular, put the same amount of time into their Mac versions, and it can be seen.
That's mostly true, but Microsoft provides a lot of tools and support for game developers using ActiveX, while apple does not have a similar program, so yes, apple is partly to blame for the lack of games on osx.