So frustrated

I dont understand how it is so easy for people who should NOT be having children to get pregnant. My husband and I are great parents. We have everything we need to take care of our son (and if we ever get pregnant again, that baby too) we do everything for our son and we always will. Yet another person I know who is in no position to have another child is pregnant yet here we are... I know I sound super judgmental, I dont mean to. I'm just upset.