>>127894189Akumatizations are seen as at least some level of mind control - it takes quite the willpower to shake off Hawkmoth, and so far very few characters have pulled it off. Chloe did it because she loved (or rather, idolized) Ladybug. Alya did it because she felt the encouragement from Ladybug herself, a feeling of being needed by someone you trust. Nino's break free was based entirely on the reason for his anger being taken away, and allowing his love for Alya to shine through (and actually struggled less than anyone else in the process). One way or another, these are exceptional cases, as Nathaniel was unable to break free due to his feelings for Marinette. It's an actual struggle for most people to break free.
Whereas Chloe, while manipulated, made an active, conscious choice outside of akumatization to join Hawkmoth in an attack on the city. She is a literal traitor to France. Sadly, not a single individual was there to witness that moment other than herself, Hawkmoth, and Pollen, so Chloe won't be going to jail any time soon.