There has been a lot of progress on the movement of gay rights but even with more states approving same sex marriage there are still millions of Americans who oppose it. Often liberals who support gay marriage will paint with a broad brush and call anyone who does not support marriage equality as 'intolerant' or as 'bigots'. These sort of insults on people serves no purpose other than to make people hide their beliefs but it certainly does not move them towards changing them. There is a big difference between people who oppose gay marriage for religious reasons and those who oppose gay marriage due to bigotry but claim that it is for religious reasons.
1. Those who oppose for religious reasons.
There is a large segment of the population who opposes gay marriage due to strongly held religious beliefs. The Bible clearly states that homosexuality is a sin and these people of faith do not want to endorse something (by making gay marriage legal) that they find to be immoral.
The people that have these views tend to be soft spoken and extremely polite. Often times people are surprised when someone that 'seems so nice' opposes gay marriage. The reason that this comes as a shock to people is that religious people who oppose gay marriage don't hate gay people. They don't harbor ill will towards gay people. You won't hear them use slurs like 'faggot' 'fag' 'homo' or 'queer' nor would you witness them mistreating gay people (being rude, etc). That is because the bible commands them to be good people and treat everyone with dignity and respect.
There really is no use arguing with them about whether or not homosexuality is a sin in the bible. It is pretty clear in the Bible that homosexuality is a sin. What is not clear is what the implications of that are in a society. The Bible never states how Christians are suppose to behave when they are ruling a society. This is based on when the Bible was written.
There are some reasonable discussions/arguments to be made with these people like how the new testament pretty clearly states that men are superior to women or that there are a bunch of rules in that no one follows (like having a women's head covered and men growing beards).
But these people shouldn't be labeled as bigots nor should they be screamed at that they should practice tolerance. There are two things fundamentally wrong with the tolerance movement. The first is that people aren't looking for tolerance they are looking for acceptance. I tolerate a screaming baby on an airplane but what gay people are looking for is acceptance as equal members of society with an equal ability to marry whomever they want.
The second problem with the tolerance movement is that it has no answer for people that they perceive to be intolerant. People will argue that religious people need to 'be tolerant' of gay people, while at the same time ridiculing their beliefs.
This is a group that does not like gay people, they don't feel comfortable around gay people and they don't want anything to do with gay people. This group often isn't particularly religious but will often harbor their feelings of resentment towards homosexuals as being religious in nature. That is because they don't want to own up to the fact that they don't like gay people and want to use something to deflect that.
It is in fact relatively easy to distinguish people in this group from the people who are actually religious for a couple of reasons. The first is that you will hear slurs about homosexuals in this group. The seconds is that they aren't particularly religious so they will have a hard time quoting multiple Bible passages and are easily stumped about where their belief in homosexuality being immoral comes from (unlike the actual religious group who will be quoting enough Bible passages that you'll have to go look them up). These individuals may be rude to homosexuals or make snide remarks either around a gay person they interact with or behind their back.