Are you slow or something? I said "stolen" because it was used earlier in different popular AVN and is quite memorable, but it was not stolen because as you were very observant CS's devs do not make their own music (as far as I know). It was just a simple observation, stop digging since there is nothing more to say about it than I already said. It is quite a unique melody, not some asset like "a park" scene which is used in like every game and I guess is just plain free park model or something.
Back to my question about self-voicing, I would appreciate any more info about it since I'm lazy AF and prefer using it over reading myself