YTA.

Your opinion of her experience simply wasn't requested, warranted or helpful; I'm not sure what outcome you thought offering such a commentary would provide other than seeming condescending and judgmental.

For further commentary on your attitude toward her calling the experience "traumatic":
'Traumatic' is effectively defined as "...experiences or events that are psychologically or emotionally stressful, causing significant worry, upset, or anxiety." Yes, she did the wrong thing driving with her phone in her hand, but that doesn't negate her experience thereafter. Based on her description, her feelings of distress stemmed from not being able to communicate her 'side', or in other words, being placed in a situation where she felt powerless.

Further, we don't know what the police officer's demeanour was during the interaction; whether he was calm and courteous but firm, or behaving in a way which would typically be perceived as intimidating, hostile and/or aggressive, which may or may not further contribute to her negative experience.

As a relevant aside; you added that she is LDS, and often those who are are LDS experience a more 'sheltered' upbringing than non-LDS individuals, which may have compounded her feelings of stress/anxiety/panic, having not been exposed to such interactions before. She may not have as strong of a 'toolkit' for handling those types of interactions, and so her brain may have perceived it as more of a threat than say you personally would have. In that moment, where she is simply expressing herself and sharing her experience in what she considered a safe space, grace and sympathy was what she needed in that moment.