Does majority always equal right in a democracy?

I have seen several posts on YA in which people have stated "let the proposition 8 vote go, the majority have voted yes" or "this is a democracy and 'you people' lost". When did the words majority and right attain equal meaning. There was a time when the majority upheld the idea of slavery, the lack of suffrage for women, the lack of suffrage for black citizens, and the policies of 'separate but equal' for black citizens. Were those in the majority right in these belief's? Few would think so today. So, why do people ume the majority is correct in denying citizens equality today?