I think he should of probably watched what he was saying, the boy has a filter problem, but he was only defending himself. Considering Rogue's own history, I think she'd be a bit more empathic with wayward youths who tend to think they can get their way with violence.
But maybe that is exactly why she's harsh on him... ? I agree with you, woulda been nice to see more of them together. It was an interesting dynamic and poor Hellion has felt pretty abandoned by his role models, which would have fit perfectly with Rogue's job at the time.