Gods and Old Gods are different in this world, the Old Gods are crafted by the Gods, shaped from the deeds and sins they committed in their previous Mortal life. Tor'qux massacred nearly 500,000 people, it's not as if he was going to be a Good Old God. The good ones aren't entirely good, and the evil ones aren't entirely evil.

Plus, this isn't mythology, these Old Gods are very much real; they are alive to keep a balance of Chaos and Order.