Since when did to become unacceptable to tell the truth?

It amazes me how many people can't take the truth anymore and lash out then act like they are three years old throwing a tantrum over a toy they didn't get. 
I have seen so many cases of this. From friends, family, even people on the net. All react the same like a three year old. 
Friends who have children seem to can't accept the truth that I am not their on beck and call baby sitter. I do have a life and I do work crazy hours at times depending on the time of year. 
I have explained that no I can't baby sit because I do have obligations and my own life and they act like I asked them to kill their child and then start throwing a tantrum. I don't mind watching their kids once and again. I will not be watching them every week because you are too lazy to hire a baby sitter because you want to go to a party, etc.
Family can't seem to accept I do not want children. This comes from the fact I feel no desire to have children. Maybe I am being selfish, but my body and my choice. 
After dealing with adults acting like children, is it any wonder why people clam up and don't speak the truth. We live in a world where it needs to be sugar coated because you may hurt someone's feelings may get hurt. That is a fact of life. Put your adult underwear on and take it like an adult.