Completely agree. If he's actually trying to smooth things over, he's approaching it with the wrong tone. "Hey, what's your problem with me?" is not a good foundation. She's also entirely within her right both to be hurt and to not want to share it, especially with the person responsible even if inadvertently.
From my reading, it feels like a combination of being offended at her attitude and wanting to secure the boyfriend position, not true interest in getting to know Mahiru. Next chapter will tell, but I doubt he'll drop the topic like he should at this point. It's clearly not a constructive conversation.