Why do pregnant teens get judged so harshly?

i am not a teen, but i am a young mother, and it really makes me cringe when i am out with the young mums from playgroup and we get filthy looks, and rude comments, don't people understand that nothing works 100%, and these girls are doing the best that they can with what life dealt them. sure they need help to raise their kids, and sure they will miss out on a lot, but maybe they didn't plan for this, i know i didn't, i was told i had gone through menopause, and i was unable to have children, so i stopped using the pill. 2 months later i find out i am pregnant.