That is true. However, truth is not determined by democracy. The Earth does not become flat just because most people believe it is.
Fifty years ago, racial segregation was considered normal by most people in the United States. Two hundred years ago, slavery was acceptable to the vast majority of people around the world. Two thousand years ago, in Europe it was considered normal to feed innocent people to lions just to entertain the public. Further back in history, in some parts of the world it was common for servants to be buried alive with their recently deceased master.
In each case, morality progressed because a small number of people thought about the ethical standards of their society and concluded that they needed to improve. We still cannot say that we have solved all ethical problems today, just as people could not say so in any of the historical periods mentioned.