There is ignorance on both sides but both sides believe they are right and everyone else is wrong.
Civil Unions should be available to all consenting adults in a country. It should convey all the legal rights of what is currently called marriage in the USA. There should be a centralized legal quality assurance to ensure that "drive-thru weddings" must go through the same rigorous process as getting married at a courthouse or else these insults to marriage (most common in Las Vegas, which has other problems as well) would not be recognized.
Holy Matrimony and equivalents in other religions should convey every religious benefit that it has always had but remain an exclusive sacrament with its own rigorous process to prevent fraud and abuse. What private companies honor should not be forced upon them by an oppressive government (it is hard to deny that the government of the USA is oppressive).
Civil Unions and Holy Matrimony are not the same and should remain separate. In order to receive all benefits, one would need to go through both processes.
Sincerely,
--Ocram
Always do your best.