Certainly one of the reasons is that he passionately believes in "heaven" and "hell" - you know, the sort of stuff wicked and deranged adults tell children about to try to make them behave:
The current Christian generation does not like to talk much about sin or hell. [CS] Lewis reminds us of these awful biblical realities. But he also reminds us of the even greater realities of the love and mercy of God, and of his Son who came to rescue us from the bondage of sin and the punishment of hell. These are truths which we all must embrace and affirm.
In the above quote I'm not sure I've ever seen the words "realities" and "truths" so roundly abused. Would Bill care to cite any evidence for the existence of eternal reward or eternal punishment, and once he's done this, would he care to cite the criteria for entrance to each?
Of course he would not. How could he? The problem is that it's all in his head, and made worse through his "interpretation" of scripture. The Old Testament, as we all know, positively recommends genocide, slavery, the routine rape of women (see the vile story of Lot), infanticide (several times) and a whole host of incredibly wicked and immoral acts that the "loving" and "merciful" god carries out - though we're told it's perfectly moral if it's God or god's chosen people doing it. In the New Testament, women are similarly treated with scorn and as something sinister and less than human, and we have the contemptible scapegoating of Jesus, and alleged vicarious guilt on everyone born thereafter. If this works for you, Bill, then fine. But leave me and anyone else who sees through the bullshit out of it.
One of the many stupid mistakes of logic Bill makes is that he thinks there's a need for the promise of heaven and the threat of hell in order for people to behave themselves, and that without the moral instruction of the bible, people would just go around murdering one another. What, like other animal species? To the theist, the reality that chimpanzees and other apes, as well as other mammals who live in groups like elephants, wolves, lions, whales, dolphins, walruses... (I'll stop there)... don't go around murdering one another, but live peacefully together and support one another through reciprocal altruism and kin bonding. They may kill to protect their own group or kin from a threat from outside, but all the above species and many more manifestly don't just go around murdering one another. To the theist this is a huge problem. Why not? How can they, without a bible and the threat of heaven and hell, know not to do that? Or do they have their own "bible" and "moral code" that they understand intuitively? To the theist - all their work is ahead of them. To the rationalist, it's clear that members of the same species routinely murdering one another would be evolutionary suicide and quickly lead to extinction. We tolerate others because of our inherited genetic history, not by believing in fairytales.
Bill's second logical fallacy is that now that he'd studied a lot of books on theology he's in a position to tell you what god's will is. Note how smugly convinced he is that once he's dead he'll be on the fast track straight to heaven.
"Look god," he'll say (OK, OK, I know there's no god as well, it's just a metaphor, go with me on this) "I spent my whole life railing against non-Christians, against homosexuals, against secularists, against liberals and accommodationists. What's my reward? Do I get to suck your cock?"
Suppose for a moment that he is right and there is a heaven and hell (I know it's ridiculous, but just suppose it). How surprised would Bill be to be told he's going straight to hell for interfering in other people's lives, campaigning to deny them rights, and showing extremes of intolerance and bigotry, and thus making the misery in the world that bit bigger?
There are obvious historical contexts that indicate clearly why the alleged bible writer Paul may have had a bee in his bonnet about homosexuals, as the practice was commonplace in the Roman world, who were after all the oppressors and foreign occupants of Judea at the time of Jesus. "What have the Romans ever done for us?" But people like Bill are too narrow and stupid to understand context or to even want to imagine for one minute that using their farcical beliefs as a prop or moral shield for their vile bigotry is reprehensible, and morally as well as intellectually null and void.
He wants everyone else to go to hell so he can be on the fast track to heaven. But by living such an immoral life, interfering with and condemning others, he's creating a hell on earth. It's a shame there's no hell for him to go to.