Because the problem is these morons take bits of the bible they like that they think goes along with their stupidity and try to twist it into something its not, it's like how they claim in the constitution something along the lines of "Congress shall
define marriage as between a man and a woman" the problem is the keyword there DEFINE which means it defines it, it hasn't actually made it illegal for a man to marry a man or a woman to marry a woman, of course, they're stupid so they don't pay attention to that.
It's like how they attack science and claim its all bullshit and yet here they are, making threads on something science created, talking on something science created, attacking science. Holy shit the irony you see in the world whenever you actually try and think about the things people say. These people are pre-programmed to spout their bullshit from an early age and they don't think about it, so when you actually try and get you to think about it they just end up repeating themselves or start trying to change the subject because they don't like having to think it.
Trust me, I've been around, it's not just you thinking about this stuff and it's a load of crap I know

they're morons and that's all there is to it.
For a person supposedly against judging you are awfully judgmental. You'd have a hard time finding a regular Christian in your day to day life as hateful of gay people as you are of Christians.
Maybe you should try to find out why people think they way they do and what they actually think (since you and the OP are wrong about what most Christians think) before you condemn them.
And the second is like, namely this, Thou shalt love thy neighbor as thyself. There is none other commandment greater than these.