Re: They say linux but...
I would say google
"steampowered "mac users" broken "orange box" directx7 "force upgrade""
However unsurprisingly google no longer yields any results but altavista does.
In essence Valve rewrote the original HL2 pack so it would work on the mac and in the process removed hl2,CSS, etc from anyone unwilling to upgrade to directx8 and the new hardware specification.
Valve's answer of the time was that they were moving to directx8 and the orange box engine as directx7 was easy to implement wall hacking ( changing the opacity of the textures so you can see all players even when they should be obscured by walls etc.)
Many people complained at the time especially laptop users who lost the ability to run an old game on old hardware, no option was provided not to upgrade and complaints fell on deaf ears.
Those that were able to run the game under directx8 complained of a massive performance drop after the "upgrade", I would say because of the additional layers of abstraction required to run a single image under IOS and windows.
Also many server operators lost money due to being unable to lease their servers out, this as the new build was both unstable and had broken all the community mods that had previously been working
So it is clear to me that Gaben is more than willing to move the goal posts on a game's hardware requirements and present this as progress, even when no additional content is added.
If you look at the number of CSS gamers and servers before and since the Orange box engine change it is plain that the old PC gamers had been written off so Valve could provide a "community and servers" for their new market( IOS ).