The "same sex marriage" plebiscite

is back in the news with a vengeance. It is set to cost the country $500m according to the media. It won't be binding either.  
Those in favour are saying it is a waste of money and that parliament should just go ahead and pass the legislation. 
It is a waste of money. The question could be asked at the same time as the next election. Both major parties should then commit to passing the legislation - assuming that people vote in favour.
I wonder though what would happen if there was a "no" vote? I suspect the same thing would happen that happened with the vote over becoming a "republic". That was defeated.
Republicans did not accept the result. They claimed it was the way the question was asked that caused people to vote "no". Since then they have been agitating, with some success, to have the issue revisited. 
If it is revisited and they fail again then they will continue to blame others and go on agitating for the change they want. They won't accept a majority view. 
I suspect it will be the same with "Scottish independence", Brexit, Irish "reunification", the right to bear arms in the US, Israel/Palestine, ISIS/moderates, and any other  apparently insoluble conflict. There will be other local issues, changing the flag, renaming sites, preserving heritage, preserving wildlife, saving a hospital or building something else. People get passionate.
          "We have the right..." they say. 
And when those agitating for the change - or the status quo - do succeed they then go on to the next thing. They are never satisfied. They need something to "campaign" for or against. They need to feel important. They need to believe they believe in something. They need to believe they can change the world in some way.
All too often they are the articulate minority. They can't accept a majority decision. 
How much conflict does this cause?