Dyani -- I've tried to make this clear before, but it didn't work too well. I'll give it another go, however.

Each state (or the people) is given all powers not enumerated in the Constitution. Defining and regulating marriage is not in there, so each state can decide for themselves how they would like to manage marriage. Since recently, things have been working pretty well, writing laws and such powers as given to each legislature by the state's constitution. But since this gay right crusade started in the 70s (and gained momentum since), it has achieved legal victories by a technique known as "legislating from the bench," whereby a minority group, lacking support from the majority of the population, could find allies willing to push the group's agenda among state and federal judges, who could redefine a law's meaning, or the state/federal Supreme Courts, who could ultimately strike a law down as unconstitutional. Many states, after the renegade San Francisco mayor broke the law and started issuing marriage licenses to gays and Massachusetts started to pave the way for gay marriage, tried to pass laws preventing anything of the sort in their states. These laws were overwhelmingly overturned by liberal judges, so the more conservative legislatures (at that time -- 2004-2005) acted in their constitutional powers to pass, in various forms, a concrete definition of marriage as amendments to their state constitutions, which cannot be altered by a few judges in the judiciary.

Now, not all states have passed such amendments, nor will all of them. That's the beauty of America -- people in various locales can make laws that apply to their immediate areas. From now on, I believe that there will be states allowing gay marriages and states allowing only civil unions (that's every other state, by the way...). This is far more fair to everyone on both sides of the issue than passing some federal-level law or amendment, since it allows far more input and customization on behalf of the people, doesn't require the federal government to overstep its bounds, doesn't impose unpopular draconian standards to state governments, etc.

Keep in mind that it is fairly difficult to pass a state constitutional amendment in any state -- oftentimes it's 2/3 of two houses of a legislature, or 3/4 of one, or 2/3 and a referendum. Referendums are clear and forceful indications that many people are against gay marriage in these states, since it requires a direct vote.

Now, Dyani, I hope with this knowledge you will realize that your question presents two choices for the reason behind this phenomena in America, two reasons which cannot possibly in the smallest part describe why these states have chosen to do what they've done.

People in these 27 states have said that they'll have no San Franciscos or Massachusettses in their neck of the woods. They've seen some effects of this so-called civil "rights" movement, and decided that it is nothing of the sort, and kept marriage a privilege for the types of people they want it to be between. It's democracy.

The bottom line here is that you may not like these amendments, but they're here to stay until people who believe as you believe, Dyani, convince them otherwise. That's why they're amendments -- people have found it impossible to exercise their will any other way because of the judges' animosity. So before calling the people who implemented these amendments "homophobic" or implying they're part of a "religious mafia" in control of the government, remember that by-and-large, these are the people you'll have to convince to think otherwise, and calling them names and thinking the worst about them isn't a good place to start.

(side note about the BSA -- I think it's only adult leaders who can't be gay -- there's no restriction on youth. And the reason the BSA is so closely tied to church in general any more is that the ACLU has pretty much cut off all public facilities from them -- schools and the like, so they have to rely on church's support. Plus, what better way to reinforce moral values than to have the support of a religious institution?)