Children “talk back” when they feel some form of injustice has befallen them. This is a form of debate they engage in with the parent or caregiver in hopes to get their way and challenge consequence.
Talking back is an issue that can easily get out of hand. There is a difference between negotiating an alternate consequence and “talking back.” Talking back is defiant and disrespectful. If allowed, it is a tactic children will try to resort to with increasing frequency as they get older.
It is important to let children know who is in charge and that your word is final to avoid this issue. Kids often outlast most adults, which can cause the adult to give in just to end the discussion. This only reinforces their strategy. Give your word, whatever that is, and try not to even engage the debate.
The bottom line is that it ultimately does not matter if they see why you have made the call you did, but they need to honor it. In time and with maturity, hopefully they can learn the "why" behind some decisions. It will be up to you to decide when you can be flexible and when to stand firm.