Why do people call 17 year old young men and women?

Because they are not yet an adult, but in their teens, so they are like a young adult.

Because it's a year before 18. In Indonesia, when you're 17, it's the year when you can get your driver's license and ID card. So it's pretty much the year when you are entering adulthood.

Also, most people enter college when they are 17. I am 17 and I am going to college in the Fall.

They are getting close to the age of the legal 'adult' age.

It is the last years of puberty/adolescence.

They are not really a 'child' but they are not really an 'adult'.

This is probably why they are 'young + men/women' ?

Because 17 is not a child or teenager anymore. My son is 17 and he is far from a little boy or a teen.

It's like, whatever, they look 18.

I'm not sure, never met one that wasn't a punk....no matter what his mommy said...

because they are fully sexually mature