“The quirk…” Monoma pauses. His irritation ebbs away and his grin reforms, likely taking pleasure in making Katsuki wait. “…lets you hear people’s thoughts about you.”
“Tch, what a stupid quirk,” Katsuki scoffs. Now that he knows the quirk he’s been hit with is nothing worth killing over, he takes a step back from Monoma. “Like I give a fuck what people think about me.”
By ‘people’, Katsuki means strangers and extras he doesn’t care about. The members of class 2-A don’t fall into either of those categories.