I'm pretty sure he needed an excuse for being bad at how humans work.

[That's under-selling it a little, but really Taako isn't entirely sure. He gets that the get up Clark was wearing is important, but Taako would have easily accepted it as just "this is a cool outfit", the whole alien explanation wasn't necessary.]

Maybe you'd better ask him that one, but you know, your secret's safe with me and whatever.

[Really nailing it here.]