The single biggest issue is that they insist on it being a "marriage" and that they will be treated as second class citizens if it is a civil union and not entitled to all the rights and remedies, despite the fact defacto have all the same benefits as married people. If it is resolved legally that civil unions are the same in terms of rights, then it should be a fait accompli.
So if you remove the legal issue, it becomes purely a reason to upset the church, which is where the issues are. Why is it ok to discriminate against religion, purely for the sake of retaliation for "perceived" discrimination. The argument then goes on to perceived discrimination and that argument completely ignores all forms of religious freedom. So to prove discrimination, you have to support discrimination against religion. The whole purpose of this exercise is to perpetrate hatred against the church, so of it perceived, so of it very valid. I am just constantly surprised by the fact the people who campaign against discrimination and bigotry are usually the worst offenders.
And yes there are idiots at both ends of the spectrum. Can't everyone just find some middle ground and move on. I have my hand up for civil unions.