Notice how it’s “Older Millennial, younger millennial, etc”. You don’t use those qualifiers with the other generations
Of course you do. I, a young millennial, have a lot more in common with my old genZer sister than she does with a young genZer born in 2011. It’s an important distinction because we both didn’t get smart phones until we didn’t have smart phones until late teens at least, while young genZers weren’t even born when the iPhone was first released.
My parents are young boomers. For my dad that means he never had to worry about getting drafted like his older boomer brothers.