To be fair I think Chloé is right to be upset.
She litteraly asked Ladybug so she knows she's close to the Akuma, which btw is her own parents, she's did a good job when she cooperated with Ladybug in the past, she was slowly improving as a person, she's strong to the point she resisted Hawkmoth's akumatization.... Ladybug knows how much she means to Chloé, knows how much she wanted to be Queen Bee and be useful again. And yet... Ladybug chooses someone else !
And it's even worse when you know the rest !
She choses someone who's identity Hawkmoth is also aware of ! She actually dismisses Chloé, and not even because of the (legit) excuse of "Oh it's because Hawkmoth might be lurking". She choses Kagami so that she can't kiss a boy, right after setting them up together! A boy she apparently gives up on right after? Like... wow ! That's why Chloé didn't get the chance to save her own parents ? Wow.
Did Ladybug even say she was sorry ? Anything to appease her ? Did she give Chloé any reason to keep trusting her ?
Sure, Chloé isn't entitled to a miraculous... But Ladybug isn't entitled to people's trust either. Not after dismissing and ignoring them again and again.
Chloé's anger IS perfectly understandable.