Call the ritual barbaric, but I'm not sure we can call the situation wrong. This lottery was the only way of life any of them had ever known. They were just starting to learn about other town's changing there ways. But if it was they only thing they'd ever known, and they didn't know anything else, how can we say they were wrong?
Old Man Warner is symbolic of the "old ways" of the town, when no one questioned the lottery's benefits (or supposed benefits). He is of the belief that the lottery has always been and should always BE. He does not like change; therefore, he wants the lottery to always continue. Mr. Summers and Mr. Graves are also of the "old school" in that they do not entertain getting rid of the lottery. Mr. Summers and Mr. Graves play important roles in the town and in the carrying out of the lottery. They perhaps do not want to give up their positions of power if the lottery were not to continue.
There are others, though, in the town that question the lottery's usefulness. Other towns have begun to get rid of the lottery and/or question its intent/purpose. This has gotten around to their town and people have begun talking about it. As the older generation begins to die off, the younger generations have begun to wonder about the lottery and why they continue to practice this ritual.
The author's intent was to point out the cruel and unusual nature of humanity and how society has become so used to it that they do nothing about it. Jackson commented about this in an interview not many years before her death.
I think a great lesson to be learned from "The Lottery" is that simply because a ritual or tradition has been done for a long time, does not necessarily make it right. The lottery in town has been done over and over and over again, however it still involves unethical principles, therefore making it morally wrong. This moral belief can be adapted to just about any society, simply so that they know that rituals and traditions are not necessarily right because they've been done forever.