See it like this, it's not often when a good yukkuri tell a bad one "fuck you" and live to tell or kill the bad one succesfully.
I had seen many cases of actually good mother reimus with a selfish father marisas who run away leaving the reimu and the kids behind when something bad happens.
In this case the good yukkuri is clearly Marisa, and it's a sad thing this comic isn't canon, we sure need more Good owning Bad moments or stories, its, ironically, one of those times on which both abuse fans and non abuse fans agreed in something (at least the majority does), yet sadly it doesn't take place that often.
In the wild though, survival favors the selfish. The selfish is usually the aggressor in almost all incidences and usually the victor, because they're bigger and stronger due to the selfish factor.
This Marisa is being pushed to the brink of death, and not only does it still coherently and actually INTELLIGENTLY think and speak, it cranks the "Fuck You And Your Fucking Little Fucks" to a WHOLE NEW LEVEL. ***waves tiny Yukkurisa pennant***