I don't think that's it. Mei wasn't giving out false hope. Yamamoto and Mei's relationship is solid and Aoi knows that. Mei is trying to be a good person. Tell me how would feel if the person you like just cut off all communications with just because you said "I like you"? Aoi already has a bad imagine of people, and Mei knows what it feel like to be cut off. Mei was Aoi first real friend I feel like. To suddenly lose someone like that hurts and feels like Aoi did something wrong when he didn't. Mei wanted him to know that they're still friends all he has to do is reach out. Being bullied Mei knows the sting of a rejection and is kinder in that regard.
Okay but Mei isn't being sincere. If you TRULY didn't want to hurt him then YOU WOULDN'T SEND HIM A FOLLOW UP MESSAGE! I was so angry at her. Like, he's trying to move on but you keep giving him false hope. (╬ ̄皿 ̄)凸