I can't really comment if Meghna should've been 'free' to practice her agency and protest in a violent way, but I would say that that was not really her 'agency', rather she was brainwashed to believe that that's how she could get even. Real power to her might have been to make her life worth living again rather than giving it up completely in protest.

Nonetheless, if she thought that was the only way, and no-one had the patience to explore another way with her, then obviously she should've had the right to exercise her decision without some dude forcing his own on her, literally.