Danny Fenton just learned he is an alien, and his powers are actually just meta-Kryptonian abilities. Reason why the blast wouldn't really hurt him, and if he let himself be shot by the GIW, they would see he is an alien and leave him alone. He's surprised when they got visited by the people; it was the superhero superhero and his family. I am very interested in them, as the Fentons are the first "non-family" Kryptonian they meet after thinking they are extinct. Jack is happy to see new Kryptonians! So Superman and his family, House EL, don't really respect boundaries. Danny and Jazz don't even full notice it, thinking it's a Alien thing as jack is the same.