well, actually, she was still doing naughty things during her time with Gen X. at the very least, she killed her sister.
now, the X-Men and other superhero teams in the marvel-verse have a history of forgiving serious crimes if the super-powered person wants to work with them. off the top of my head:
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X-Men who willingly committed crimes (not going to go into all the characters who committed crimes while mind-controlled)-
Rogue- worked with The Brotherhood for several years, stole Carol Danvers' personality and powers.
Gambit- thief; organized the group that committed the "Mutant Massacure", unaware of what they were going to do, but knew they were up to no good.
Nightcrawler (yes, even Nightcrawler)- killed insane stepbrother who was murdering children just before joining X-Men.
Juggernaught- worked with The Brotherhood/Black Tom for years and years, until very recently.
Wolvie- you can't tell me he hasn't purposely gutted anyone off-panel
Angel- willingly joined Apocolypse, became his "Death"
Magneto- on-again/off-again X-Man, founder of The Brotherhood, has killed at least the crew of a submarine willingly.
Colossus- served Magneto as an alocyte for a time, but I don't think he did anything of note during his tenure.
Storm- thief in Cairo as child
Marrow- member of "Gene Nation", terrorist organization who aimed to get revenge for the "Mutant Massacure" and other atrocities.
Emma Frost- willingly served with the Hellfire Club during some nasty business. she herself helped drive the Pheonix insane, tried to mind-wipe Storm, "mind-raped" Iceman, and as I noted, has killed at least one person.
other heroes/characters of note-
Scarlet Witch and Quicksilver- served with the Brotherhood at the beginning of their careers.
Hawkeye- thief, fought Iron Man.
Black Widow- Soviet spy.
Black Panther- Wakandan spy.
Moira McTaggert- tried to mind-control Magneto by altering his genes.
Sunfire- tried to destroy Washington D.C. when he first recieved his powers.
The Thunderbolts- entire team of criminals who participated in the break-in of the Avengers mansion.
other incidents of note-
Scarlet Witch- recently went insane and killed members of the Avengers as well as altered the entire dimension to her specifications.
The Pheonix force- when it took over Jean Grey's apperance, wiped out an entire system on a whim.
Sandman- obviously hs done some naughty things, but recently it's been revealed that he has a personality disorder; served with the Avengers for a time.
Mystique- leader of The Brotherhood, has allied with the X-Men at various points in her career.
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now, in the face of all these heroes who have committed crimes, how does Emma Frost stand out?
she doesn't show any remorse for her actions, and leads me to suspect that she would commit more if she wished to. everyone else (except Mystique) are trying their damndest to make up for their crimes, justice in a way. Has Emma even apologized?
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so what do you think of Emma's repentance? is it genuine?