Does it say I need permission? And do you even care what the TOS says? I mean, you're selling mods, so clearly you don't. You're just being a hypocrite.
What this says is that you grant Giants usage rights. They spell out those rights. And then they state other users can use those mods. You also revoke your moral rights, which means you can't have an issue with your mods being used in a variety of ways, including being transformed.
You can keep saying, it doesn't say this specifically, but just because you can't understand it, doesn't mean its not there.