Why are you answering a question with a question?  can it mean that you know it's not just?  

Why is it just that some live in a larger house than me?  Why is it just that some have a nicer car than me?  Why is it just that I have to shop the sales at the grocery when some can just buy whatever they want regardless of price?  Why is it just that my phone is 3 years old and some have the newest?  Why is it just that some kids can go to better schools than mine went?