How is releasing source code under a commercial license considered "opening it up"? All this stuff was already available to modders/third-party devs through the SDK program. The only news here is that they made it available on Github.
Opening it up as in making it easier for the general public on Github to view. No need for the cynicism.
"You may, free of charge, download and use the SDK to develop a modified Valve game running on the Half-Life engine. You may distribute your modified Valve game in source and object code form, but only for free."
Sure, you can't make commercial products out of it, but you are allowed to re-distribute any modifications for free. This can be used by people who want to make free, open source games, for example.
"1. Free Redistribution The license shall not restrict any party from selling..."
Properly speaking, "commercial" is an orthogonal concern to "Open Source" -- if software is sold by a merchant under a license, that license is commercial, whether or not the license is also an Open Source license.
You seem to want to create a new use of "commercial" where it on a continuum with "Open Source" but not merely the negation of "Open Source", such that there would be "Commercial" and then some poorly specified "gray area" and then "Open Source". I'm not sure that this is either a particularly good use of the term "commercial", nor a particularly useful concept regardless of the terminology. Non-Open Source or non-Free licenses always permit you to do something with the software (that's why they are "licenses").
So my original point about the license not being properly commercial stands. I do agree with you that it is not really proper to claim that there is a spectrum between commercial and open source.
In reality, the 'opposite' of Open Source is proprietary. There is commercial Open Source (Red Hat), and proprietary software with source code available (Unreal SDK).