Why do so many people care about other parents' parenting skills?

Women get slammed for having a baby at 18 or at 40. We get slammed for feeding or choocing to use formula. We get slammed if we work or if we stay at home with our kids. We get slammed if we or use time-out. We get slammed if we use daycare or if we don't use daycare. We get slammed if we're divorced or in a non-marriage relationship. We get judged if we waited until marraige for or if we chose to have premarital . Why? Aren't we all parents that care about our kids more than anything? Aren't we all doing what we feel is best for our children? What does all of this have to do with the type of parent we are? I may be venting just a little, but I had to get this off of my chest.