One the one had I can understand Mystique's inner dilemma. She feels that no one will accept her for what she really is because she's blue and scaley. They only like her when she puts on a facade. Who can't relate to that? I've pretended to like football to make friends, even though I've only watched three games in my entire life. It's exactly what being a teen can feel like.
Where that falls apart is that other people can't literally change themselves. Who cares if no one likes your blue and scaley self if you can literally look like anyone. She can be whoever she wants. I have to pretend to like football. I'd kill to actually like it. Ultimately it comes down to the fact that I actually dig the blue skin and scales, so I have no sympathy for her.