If I could lead the cat herd, we'd make a few changes. Why?
For a start, I don't see moderate/liberal religion as a terrible problem. I've really never bought into this element of what I see in, say, the work of Sam Harris. Some forms of liberal religion are so non-literalist that they can't even be considered incorrect - they make no or few truth-claims about the supernatural and see the holy books as historical documents to be studied for whatever wisdom they contain, much as we study The Iliad. These sorts of non-literal religion are potentially all consistent with each other, and also with humanistic philosophies.
Even more literalist religious positions that involve a belief in some kind of supernatural order may be no great problem, and indeed they can inspire people to do good. I'm not going to say that Martin Luther King was a bad guy just because he believed in some (probably heretical) version of Christianity.
These kinds of religion only become a problem when their leaders tell critics of religion to shut up, and try to convince everyone that almost all religion is harmless or even beneficent. Thus, Karen Armstrong is fine when she enunciates her own positive religious understanding. She only becomes a problem when she tries to convince people that all religion is "really" like that and we should stop being so nasty about it. I can't imagine her ever flying a plane into a building or even trying to introduce draconian laws that restrict personal freedom (though perhaps I'm wrong about the last bit). Really, if she'd just offer her positive message and stop trying to deprecate the less savoury aspects of the religious traditions, we could get along.
Note, though, that Armstrong is no worse than an explicitly atheistic accommodationist like Chris Mooney. It's not her mild religiosity that's the problem; it's her urge to dampen a necessary debate about the place of religion in modern society.
Still, the real problem is not religion in itself. Many of the pagan religions of antiquity, after all, were not so bad. They didn't have very much of the elements that I'm about to identify. Indeed, those elements are very largely confined to the Abrahamic tradition. To some extent, they turn up in the Eastern religions, but much less so.
The problems are apocalyptic and totalitarian thinking; the accompanying spirit of intolerance and exclusivity; misogyny, sexism, and shame about the body; and associated homophobia. Greek paganism certainly had more than its fair share of sexism - it's easy to find this running through the myth system. But the other things just listed ... well, not so much. Ancient paganism wasn't totalitarian, or apocalyptic, anywhere near as intolerant as Christianity has proved to be, or anywhere remotely as obsessed with sexual sin and guilt. If Greek paganism made a comeback, it would have to adapt to the idea of women's equality, but otherwise it wouldn't be a huge issue. It wouldn't create Crusades and jihads, suppress art and science, persecute homosexuals, or torture heretics.
By contrast, much in the Abrahamic tradition is totalitarian, apocalyptic, arrogant, officious, intolerant, misogynist, homophobic, puritanical, prurient, and persecutory. The totalitarian, apocalyptic, and persecutory elements, in particular, but also some of the others, were taken over by various ways of thinking they sprung from the Abrahamic tradition, notably the apocalyptic cults of Nazism and Marxist-Leninism. Then there is the specifically anti-Semitic intolerance that looms so large in Christianity, and which led directly to the Nazi holocaust.
But there are modern forms of Abrahamic religion that are politically liberal and not apocalyptic. Some of them have also purged themselves of the other stains on their tradition - the misogyny, etc. I don't see adherents to those forms of religion as my enemies, for much the same reason as I don't see religion itself as the real enemy. In the American culture wars, progressive religious people have defended such things as gay rights, abortion rights, rights for women more generally, racial equality, and freedom of speech. In recent decades, organisations with large numbers of religious adherents such as People for the American Way have been invaluable in the struggle against creeping theocracy.
So if I were leading the cat herd, I'd like to stress that the problem isn't so much religion in itself, or even the Abrahamic tradition in itself. It is, first, the many deplorable elements - the apocalypticism, totalitarianism, sexist, puritanism, intolerance, etc. - that are so prevalent in the Abrahamic holy books and traditions. But it is not every single element of those traditions.
And more proximately, the problem is whatever systems or styles of thought have absorbed the worst elements of Abrahamic tradition. This includes the worst kinds of apocalyptic communism, Nazism, and fascism, all of which arose from Christianity.
I think the above is (1) more accurate than a line that identifies religion itself as the problem, even when the religion concerned is entirely or relatively anodyne; (2) principled in identifying the real problems that have come to us, historically, through the Abrahamic tradition in particular; (3) likely to help us deal with mildly religious people who share our political values and are just as repulsed as we are by the more barbaric elements of their traditions.