I do think that it is very important for a child that age to be cared for by others sometimes.
We have this myth that children were traditionally kept home with their mothers 24/7. It's not true at all. Throughout history, most women have worked outside the home - whether it was as an nurse, selling in the market, picking in the fields, sewing, etc. It was only the very rich women who could afford to stay home with their children all day.
Throughout history, children were typically cared for by other members of the community. Grandmothers and other women in the community... I don't see any reason why they would be less safe in a daycare setting. If anything, they will be safer today because of the training, rules and guidelines that most daycares must follow.
I think that in today's society, we're so isolated. Women are taught to think that it is wrong to go out and work, and that they are not good mothers unless they stay at home, bored and unstimulated, with their young children. I think that it prevents children from learning how to negotiate and play with other children. Also, your child will learn in daycare that he is not the center of the universe. It is healthy.