Originally Posted by X-Maniac
The X-Men are perceived as a threat, an emerging new species that - as the films keep telling us - could do what Cro-Magnon did to the Neanderthal. The general policy of hiding in the shadows to avoid discrimination is sensible, but is perceived by humans as making them even more unknown, furtive and sinister. They're perceived to be vigilantes with hidden agendas.
But the movies can show that stance and not be questioned because the only superpowered beings in that universe are Mutants. There are no Super-Solders, Demi-Gods or Gamma Radiated Monsters to show any other potential threats. It'll be a little more complicated to the GA if the films were to be in one universe like the comics..