Why are kids so disrespectful now? And why do parents allow it?

I have two kids. They will be disrespectful and back talkers if we allow it. With my oldest, when she entered the "Terrible Ten's" which is repeat of the Terrible Two's but more vocal and with more attitude. Ten year old's are starting to assert themselves and often don't know how to do it. I find listening, listening and then more listening works well. I try to listen to more what they are trying to say then how they are saying it. If they are disrespectful, I address it after they have told me what they are trying to say.

I am far from perfect, and not even a good parent some days, but this works for me.