Welcome Riggamortis, I don't think we've met before.
If you presuppose the bible is true, you can easily dislike people just for being gay, for example.
I don't really agree with that - if a person applies the entire teaching of the Bible to his/her own life, it's not going to be easy to "dislike" someone who doesn't interfere with Bible believers (Christians) lives. What causes most of the dislike today is when gay people suddenly want brand new insertion of their lifestyle into the traditional public institution of marriage.
Which common atheist presuppositions pose a threat to society and how?
The main atheist presupposition is that life originated from naturalistic processes, something they can't prove. Further, their presupposition that there is no God leads directly to their belief that humans are the highest form of intelligence, and basic principles that the U.S. was founded on, like the 10 commandments, become subjective. This quickly balloons into lopsided political opinions, like a fear of global warming.
As an example, there is really no serious threat by the Christian community in the U.S. to give authorities permission to force their way into the private bedrooms of gay people and declare what they're doing to be illegal. But there IS a threat by the secular scientific community to demand that automobiles,
after they're sold to a private owner, be monitored and regulated in how the engine is equipped, in the interest of controlling pollution standards that they themselves set.
But my main point is that those with any type of naturalist worldview have presuppositions that are comparable in number, severity, in EVERY way, to the worldview of religious people.