The problem with kids that want to solve others' problems, and their own, on their own. And listeners more than talkers.

Adding in this Frisk's extra-strong attachment to an Asriel, they don't want to go into their own issues involving him. Especially since this Frisk probably contributed to their Underground's problems and Chara having to fix them (probably? or things to FIGHT. one or the other) and might make them feel worse.

They rehash what they've already said. "It is. Okay as it's gonna be for right now," they say firmly. "Feel bad about being mean, but I'm gonna fix it, and then it'll be more okay. It'll just take some time."