You'd be surprised how vocal people will get, even in person, when it comes their religion and beliefs. Yes, people feel bigger and stronger on the internet (I'm sure we're all guilty to a certain extent... enjoying anonymity). But, I've been in situations with individuals where I had to tap-dance very carefully (get my points across without making them defensive) to avoid further escalating a tense situation. I was uncomfortable, to say the least.
When people don't have facts or evidence on their side, then they resort to the least common denominator -- violence, be it physical, or verbal. Hence why most anti-gay individuals bust out "fag" and other slurs to play on people's emotions, fear, and hatred.
Keep up the fight... equality for all... someday!