Pecuz they go to publik skools otherwise known as Indoctrination Centers for over drugged, badly behaved Morons!
Bingo...add in the constant misleading information from major media outlets, and a lack of critical though by those coming out of our public schools...and there you have it...a democrat party line voter.
They are starting the indoctrination younger and younger. This was all part of a Marxist plan Hillary and Bill implemented in Arkansas. That to make the societial changes they feel is necessary they had to start in grade school with the brainwashing.