Because when you were born correlates with your cultural experiences and therefore your behaviors. Not always, bit broadly. And if you try to define groupings for those years, you can see clearly defined generations, that were really clear with the baby boomers, who were the American children of American soldiers coming back from world war 2, and then their resultant children, generation y/the "millennials", named thusly for coming of age around the time of the millennium.

Like sure, it's all social constructs. But, so is language.

Baby boomers generally got some of the biggest economical booms in history, along with the population "boom" of their births. But that was only if you were able, white, cisgender, heterosexual, and male. The civil rights movements of the 50s, 60s, and onwards were both possible but also necessary because of the empowerment of those demographics.

But also, because of that general success, a lot of baby boomers (cishet white men) took on the behavioral traits of being largely pieces of shit. Not all, just like "not all men". But, it's enough of a pattern of entitlement and sexism and repression and psychosocial behavioral resultant of lead poisoning, that that's what the baby boomer generation is kind've seen as, now, regardless if any individual does or doesn't fit any of those things.

And so, we can largely group and label the generation and attach it to a current age group and try to predict or explain behavior.

Unfortunately, this is also discrimination in many cases where it isn't true. Personally, I try to avoid profiling entirely because the habit is gross. But, I would be lying if I said I didn't clearly see a solid pattern. I know, that they're just people like the rest of us, and if we were in their shoes, we would entirely end up just like them. But then that again brings it to it being generational, and not just age.

You think I like being reminded and disappointed when people end up fitting their negative stereotypes? You think it's easy to try to be a good person against my own upbringing? It's not. But we have to try. And working to understand is a big part of that. More people need to ask "why", and, I know you were asking rhetorically, but you were close enough that I think it deserves recognition. So, good on you for that.

Whatever the millennial generation ends up being known for, I'm curious. But until then, we can't give up trying to make ourselves, the world, and each other better. Because once you give up.... Well... We can never give up.

"Why not?" Etc etc.