Those states voted to uphold traditional marriage. They already have equal rights, it's not a bad thing that others are allowed to vote and not have views and definitions that are wrong for their society thrust upon them by a minority or special interest groups. People voted, the outcome just isn't what some like and thus a persona of "inequality" is pushed when everyone did have an equal vote on an issue of social policy.
As far as the last state goes, I'm not sure. Many of them have traditional marriage legal at their constitutional level, they would have to go through the process of amending their state constitutions to change that.