So you're ticked off when religious groups who disagree with you get their way and you don't? That's understandable.
That's not what I said. The issue here is not whether I or anyone am "ticked off." The issue is when and whether a law, imposed on everyone, reflects a religious doctrine only, without a secular purpose, and thus violates the separation of church and state. This can be a tricky question, as Supreme Court rulings have demonstrated. It's tricky because many laws, perhaps most, are both consistent with people's religious doctrines and expressive of a secular purpose, or a broad social need or social good. When that is the case, there's no problem, and the Supreme Court has recognized this with its Lemon test. Overlap between religious doctrine and a secular purpose, or broad interest in the common good, is fine. The problem arises when there is no overlap, when a law is enacted purely to impose a religious doctrine on everyone in the society.
Your argument earlier suggested that majority rule would tend to reduce the likelihood of this occurring, and that may tend to be true, but it isn't always or necessarily true. You have also noted that a majority of Americans are religious, and this is true depending on how one regards "religious." Many Americans are nominally religious but not actively so, and there are people of minority faiths and people of no faith. For the majority, who may embrace certain religious doctrines held by Christians, to impose those doctrines on those of minority faiths or of no faith, is to impose a particular religious morality or viewpoint on people who don't subscribe to that religion or to that morality.
Same-sex marriage is a clear example of this. The majority may oppose same-sex marriage based on their religious beliefs, but a significant minority holds different beliefs and supports same-sex marriage. Civil marriage, as the Supreme Court has ruled, is a fundamental right, and it's an institution that protects and benefits families and children. Families and children are disadvantaged by couples not being granted the equal right to a civil marriage. I don't care that many Christians oppose same-sex marriage. They are free not to recognize it in their churches and not to perform same-sex marriages. I do care that I am not permitted under the law to protect my child through legal marriage because of the religious beliefs of many Christians. I have no problem with people holding whatever beliefs they want and practicing their faith, but when they impose their religious beliefs on me by denying me equal treatment under the law, then their expression of their religion has gone too far.... intruding into the state in the form of laws that govern everyone, including people who do not hold their religious beliefs.
A similar situation used to exist with inter-racial marriage, which was banned by state laws for most of American history. The Supreme Court struck down the laws banning inter-racial marriage, not on the basis of the establishment clause, but on the basis of the 14th amendment. However, I would argue that state laws banning inter-racial marriage also violated the establishment clause, because they were rooted in religious beliefs solely, and they were the imposition of some people's religious beliefs on everyone else. But the plaintiffs, the Lovings, did not base their lawsuit on the establishment clause, and the Supreme Court did not rule on that basis.
You may ask, but if a majority supports the laws, isn't that enough to justify them? I would answer no, majority opinion alone does not determine what is constitutional. That's why we have a bill of rights and the 14th amendment, which requires that states grant equal protection of the laws to all. The U.S. constitution provides protections for the rights of minorities, including people of minority religious beliefs. As I said earlier, we secure our rights most effectively by winning over public opinion. But sometimes to win over public opinion, you have to win first in the courts, and public opinion follows. This was certainly true with the African American civil rights movement, where the Supreme Court issued the rulings, and the movement worked nonviolently to get the rulings enforced and to change public opinion. In the case of the women's suffrage movement, the activists did not win initially in court; the Supreme Court ruled in the 1870s that although women were citizens, the right to vote was not guaranteed by the 14th amendment or by the U.S. constitution at all, and it was up to each state to determine whether women could vote. Activists had to win over public opinion state by state and eventually to win a constitutional amendment to enable women to vote nationwide. It took them more than half a century to achieve.
There is often a dance that activists must do, tacking back and forth between working through the courts and working at the grassroots to win over voters. This back and forth process has been pretty effective in certain states in gradually winning marriage rights or civil unions for gay people who form same-sex couples. We have seen a mixture of court victories and legislative victories, and in many states, so far, we have seen mostly defeats at the hands of voters. But we aren't giving up.