Maybe someone has pointed it out already, I don't know.
Has anyone noticed that the images Mr. Pratt provided were of medics? As I understand the usage of the Red Cross, it can be used by medics on the battlefield. So here we have a virtual world that is using the symbol as it's used in real life. How exactly is that misusing the Red Cross? At least in Half-Life 2.
I can understand that Mr. Pratt doesn't want the image misused, I don't either. But at the same time, Valve hasn't really used the cross in a way that is contrary to real life situations and likely to cause "confusion" in it's use, or even as logo for their business.