I think that it’s fairly safe to say that Lynn hates it when people stand up to any sort of verbal or physical abuse. The most recent example of this is when Elly’s response to one of John’s more casual forms of cruelty was to maybe think that she should smile and let a narcissistic jackass demean her all in the name of taking a joke and getting along. We also see this need to avoid the horror of complaining to the person you’re complaining about when Lizzie is depicted as being weak and spoiled by telling her parents about some of the nastier things her whiney little puke of an older brother does to her. The premise seems to be that nice little girls smile and take crap from malicious chunks of flotsam who will never grow out of thinking that life is a zero-sum game; to do otherwise is to be a tattle-tale.
This snitches-get-stiches ethos that pervades the strip seems to have its source in Lynn’s past. Most of what she’s revealed about herself tends to indicate that she herself was the terror of her playground. Since she seems to have it in her head that being weaker is a sign that a person deserves to be picked on, the idea of her reign of terror being overthrown must have terrified and disgusted her. Thus the need to insist that the only solution to her aggression is to smile when she torments someone. Alerting authorities to an act of malice and forcing a hateful little bitch to see that other people’s feelings are as valid as her own isn’t the right thing to do; to a person who can’t see that we’re not all as monstrous and vicious as she is, it’s tattling and tying her hands behind her back so she can be the helpless victim.