We haven't come too far though. Throughout most houses at Cambridge University between 1890-1950's economics was called the gay science simply because an overwhelming majority of the academics participated in same sex relations. On the other hand though, these same people were very influential with respect to public policy / government and would never have condoned same sex relations between anyone in the general public. In fact, the many of these academics even had wives.
It all goes back to the divide and conquer strategies of many religions and not only has it captured religious types it seems to have grabbed a few atheists and agnostics as well.
In my family I have several gay members and none of them or their partners would be offended by the poster, and none of them think gay marriage should be a priority given other aspects of society require far more urgent attention.
Hence, when people automatically assume that a few loud individuals speak for the entire group most times you are going to be missing the truth by a fair margin.