Thin or heavy should never be a deciding factor for talent or no talent. Everyone has a different body type and how an individual feels about themselves and their health is more important than what the public thinks. Daisy Ridley should not apologize for being thin regardless of whether that fact had anything to do with her landing a particular role.
Daisy Ridley should not feel the need to apologize for her thinness. Everyone's body is different, and no one should feel ashamed of how they look. An overweight person who takes up almost two airplane seats doesn't need to apologize to the neighbor they are squeezing next to; why should a thin person apologize for making the overweight person feel bad?
The idea that someone is too skinny, too fat, too this or that for a role makes no sense to me. The argument seems to be she's promoting an unrealistic body image. Context matters though, and it's in a very, very unrealistic movie about space ninjas and droids. Furthermore, the character is supposed to be thin, as she's a very poor explorer who gets daily exercise and, going by the movie, never has enough money to properly feed herself.
While there is a trend towards casting very slim actresses in high-profile roles at the expense of women of a more average size, this is down to casting directors and film studios. It is not the fault of an individual actress that she was cast in a role and they shouldn't have to apologise to fans for the shape of their body.