You might be thinking of the anti-spalling coating on the front. Not exactly required but helpful.
That layer traps the prices of the splattered bullet after it impacts the plate. Without it those pieces can hit your chin or arms.
OR you’re thinking of ceramic plates? Ceramic breaks up the bullet while the Kevlar behind it catches the slowed and broken pieces.
Idk, imagine being called a child, boy, preteen, teenager, or young adult when you’re in your late 20s or older.
Hearing your friends say “the boys” or women hearing “the girls” is endearments between friends, not strangers.