If the assertion can be backed up by evidence presented in the material, it's valid. What you were thinking while you were writing the story means nothing once you open the work to the public. No matter what you were intending to do specifically, if someones analysis, interpretation, or reading of your work can be supported by textual evidence then it's valid. Transformers 2 is a great example, actually. Was Michael Bay consciously thinking to himself "Hmmm, I'm going to depict 99.9% of the women in this movie as impossibly attractive ****ty girls because all women are good for is eye candy"? No, I don't think he was doing that consciously, but since 99.9% of the women in Transformers 2 are impossibly (almost robotically) attractive ****s, the inference is valid.
It's incorrect to assume that bringing up issues of race and gender in regards to Transformers 2 is due to people "looking" for the issues. They're brought up because the issues are glaringly presented in the work. Art doesn't "belong" to the artist (in the sense that the artists intentions are not the only valid interpretation of the work) once it becomes public.