Nothing was "stolen".

Without copyright there was nothing that was removed from Valve. It is just a copy.

False, a trade secret was stolen, and said employee did not have the right to copy it or disclose it.

Wait a sec... so get rid of patents, copyrights but leave the concept of trade secrets? How does that make sense?

You can't outlaw companies keeping confidential information. And you certainly can't legalize its theft and maintain a functioning market.