I can somewhat understand what Marichez was trying to do. It's something like "Leave me alone! Ah, I get it! if I say mean things to you, you'll hate me and leave me alone, right? It's okay because you'll just hate me! I'm the one who will be hurt by it!" And there's also a bit of "You don't understand how I feel!"
But she failed to realize how much Alcarto will get hurt by her words (and also the collateral damage to Sigrid).
I'm not condoning her action. What she did was definitely wrong. It's just that... I've done something like that before. And I lost a few friends because of it. It's kinda lonely.