I don’t think she meant to insult you. I feel like her reaction was based on her perception of possibilities:
1- random person takes significant time to provide advice on her purchasing decision (anything longer than someone saying yeah I’d buy that or no that’s crap try Lowes is abnormal)
2- random person happens to have a significant knowledge about flashlights (95% of the world is unaware flashlight enthusiasts exist)
3- random person provided detailed advice on multiple places where she could buy a better alternative product (clearly she’s the type of person who goes to a big box store, buys what she needs and doesn’t investigate her purchases unless it’s something like an appliance, car or house - which is normal for most people)
You may have perceived her comment as negative but to me it seems more like she thought you were so knowledgeable and helpful that you must do that for a living!
Keep on making this world a better and brighter place!