"They'll learn. I've tried grounding them and disciplining them in every form and way, and this the only way I can get through to them."

What a tard. If someone treats you like shit and there's nothing you can do about it, you just learn how to avoid them and become indignant. People only change when they want to, and they need experience to change their minds. Kids are cruel and disrespectful because they don't know any better. It takes a lot to learn how to think critically while being constructive and objective and not just rationalizing, especially when it comes to other people. You don't just oppress your kids until they change into whatever you want.