It is kind of disrespectful and judgmental to call out anyone who have exhibited rudeness or other not so socially acceptable traits that they have no values or they come from parents with no values.
Societal values may change. For example, for many parents, they perceive talking back as rudeness or being disrespectful, to the child, they may perceive as trying to assert and express their own viewpoint. If a message you send or action you take is experienced viscerally and personally, you are perceived as rude. To be able to express yourself adequately without being seen as rude and disrespectful takes a lot of experience. We should give kids a chance to learn instead of judging them as simply being rude or disrespectful. They are in a natural development phase where they are finding their own identity.
Kids learn at their own pace. There are kids who mature faster and there are also kids who do not develop their frontal cortex as fast as the others. There are also those who are wired differently, perhaps with ADHD or ASD who may have difficulties catching up with the others.