"It confirms the opinion most other civilizations harbor about Midgard: That your realm has not really evolved far enough yet to consider interacting with it."

Which has been the general way Earth has been viewed so far - With Asgard for some reason protecting the other planet. More or less. Loki knows way too well just how much Odin truly cares for Midgard. Which is yet another reason Loki would argue why no one should question his rule.