No, you miss the point. Marisa loves her children so very much. As they travel they like to randomly stop and do rub-rub to show just how much they love each other.
"Mawisha wanna do wub wub wid myommie while we waytch fo alish!"
Well if you're going to be obtuse, then all Marisa's are evil, all Reimu's are greedy, and all Alices are rapists, but that's not the way it works. Stereotypes exist in the yukkuri world too you know. You can tell what a yukkuri is thinking by it's face and as you can see, this is a warm, loving family. Stop decreasing the sadistic value of this picture, dammit.