She lied because she had to get naked in a film unless she comes up with a new script, and if she reveals that, it would make Umeki, who she considered her most important friend, look bad. She absolutely can not tell the truth. In a way, if you consider her to be the screenwriter, she is saying a half-truth as she did quit because she couldn't come up with a worthy script (it always got rejected).
Her having no interest in movies was just something she couldn't lie about because she was bad at lying. She tried. She's rude about it because just like Fuyumine, she has a communication disorder. He was very insistent on it and it will get anyone annoyed, intimidated, or put off.
Afaik, readers didn't like Ena because she seemed lazy, has a short attention span, and dissed on movies.