However, a candidate's thought process on this issue gives the voter an idea of how the candidate thinks about things, in general.
Which is how I feel. Politicians have had a tendency to move towards supports for civil unions/equal marriage and LGBT rights in recent years. This is either a genuine change in belief or the product of changing attitudes in society so that expressing support doesn't result in sh-t being shoveled onto you (see Gerald Ford for details)
So when a national politician starts going
backwards on LGBT rights in order to compete for the highest office in the land that gives me a clear indication of the sort of politician someone is.