Had this been just a mod, no problem, but as a game that costs as much as it does, it's a slap in the face.
Now, I could definitely be wrong about this, but last time I knew, just because you have a full license for Source, it meant you had access to many of the hl2 models available (and maybe some from other games but I'm not sure), NOT that you could copy/paste whole sections of another game into yours. They have a license for the source engine, yes, but that only extends so far.
You're right about most of these not being stolen, but I feel that you're off on a few issues.
