You're assuming they would fight as organized armies on battlefields. There's nothing in recent history of violence by fundamentalists to support that. Eric Rudolph used bombs... In fact most of them have only resorted to firearms solely for the purpose of well planned assassination-like attacks. Bombs, incendiary devices, or even mail bombs and anthrax would be the more likely tactics... if you go by recent violence from fundamentalists. Over 550 times they've sent out Anthrax hoaxes to abortion clinics. Over 185 bombings - Over 1500 cases of Assault & Battery, Vandalism, Trespassing, Death Threats, Burglary, Stalking. No cannons, armed militias, or anti-gay naval forces firing on gay beaches. Just the well known fundamentalist terrorism that's been going on since the mid 1980s against abortion - but focused on gays for a change. They've only committed less than 30 murders with firearms, but that could change. Going to crowded gay bars or gay events with several magazines of ammunition might be appealing to them... but then that is not a true civil war but just fundamentalist terrorism.
I've been warning people for a decade about how bad things may get. People seem to have forgotten the terrorist acts, property damage, violence and murders over abortion - all by fundamentalists. Having lived in a city that had three murders by two "reverends" - two bombings, several cases of arson and vandalism over it, and countless assaults on employees and patients it's hard for me to forget.
Four things need to be said about this.
1. The very same people whose rhetoric precipitated the violence over abortion are the very same people whose rhetoric over gay marriage is easily ten times more dangerous than the things they said about abortion. Several "ministers" have spoken of civil war. Bryan Fischer of American Family Association's radio broadcasts has said the issue will be settled "by ballots... or bullets. With their known history for violence along with their current rhetoric, only an idiot would not take them seriously.
2. Do not ever for one minute underestimate the potential of an Islamic factor in this. Here we have a large fundamentalist "university" whose students routinely protest with signs and yelling at patrons of restaurants and nightspots. It's not unusual to see young Arabic men joining them.
3. Becoming a proficient licensed gun owner is something to think about not only for your own well being but the well being of many others like you. It's more sensible to have a gun and never need it than find yourself in a situation in which a gun could have saved your life and the lives of others. Speak with a gay or gay-friendly law enforcement officer for more advice and resources.
4. Even if you choose not to own a firearm, learn to observe strange behavior of people, and never fail to alert security or police to anything you see that's suspicious at gay bars or events. Do not be afraid to take pictures.
Here's a list of abortion violence that continues to this day. https://en.wikipedia.org/wiki/Anti-abortion_violence
Here's a partial list of local anti-abortion violence.
This city was a focal point for anti-abortion crime from mid 1984 to mid 1994. (We expect it to be the same for violence against gays)
1984-JUN: An abortion clinic was bombed.
1984-DEC: The same clinic was bombed again.
1986-MAR: A second clinic was broken into and vandalized; two female employees were assaulted. John Burt, a former member of the KKK, and his daughter were tried and convicted. John Burt became the local leader of Rescue America.
1993-MAR: Michael Griffin, allegedly a member of Rescue America, assassinated Dr. David Gunn outside an abortion clinic. Griffin's lawyers claimed that Burt had brainwashed Griffin into committing the killing. (There is a consensus among mental health professionals that this sort of "Manchurian Candidate" programming is impossible). Griffin was convicted and given a life sentence.
1994-JUL: Paul Hill, a former Presbyterian minister and leader in Defensive Action assassinated a physician and bodyguard outside another abortion clinic; he also wounded the wife of the bodyguard. He was sentenced to both life imprisonment on federal charges, and execution on state charges.
2012- FEB: Pensacola, Florida, A federal grand jury indicted Bobby Joe Rogers, 41, of Pensacola, Florida, for the alleged arson of a women's health clinic in Pensacola the previous month. Rogers allegedly used a Molotov cocktail (a type of incendiary device) to set the fire.
More info with a chart- they don't even mention murders in the first paragraph. Imagine that. http://www.religioustolerance.org/abo_viol.htm