I made a big long rant about this recently, but here's a simplified attempt at explaining my earlier thoughts:
For the most part, there are two major ways religion can be practiced.
Way #1 (aggressive, dedicated religion) tends to incorporate following what the rulebook says, power-jockeying, control of others, unbelievers = the enemy/must be converted or destroyed, dislike of the unlike, and fear/paranoia/denial of any sort of reproach. People who go this general direction tend to be unwilling to think and consider other perspectives or even admit they exist, and think everyone should work the way they want them to. How much this viewpoint bleeds into your life depends on how strongly you believe in it and how ambitious/power mongering you are. This Jerry Falwell seems to have been very high in both regards.
Way #2 (passive, faithful but reserved religion) is to kinda say screw the specifics, the rulebook isn't absolute, and you should use your heart/follow a moral code in which the good of others is ranked above what you believe or prefer, and enforcing your ways on others is a bad thing. In other words, this general viewpoint is laxer, kinder, and, while still religious, goes only for the main ideas and high points that believing in something can hold, EG afterlife, creation, ultimate forgiveness, that sort of thing. The warlikeness, political elements, power-mongering, domination, etc, are all dropped. From what I have seen, Prr and Glenn are examples of this sort of belief.
Christianity/judeism/islam seem very much to have DEVELOPED along way #1 in nature, and the bible is full of some pretty horrible stuff. However, modern belief and individuality (I'm sure there were people somewhere who thought this way, though they probably didn't dare to speak it, considering they were often surrounded by things like people were being burned at the stake for- SUPPOSEDLY, not even with legitimate proof- practicing a different religion such as wicca... not that wiccans went around burning christians for being christians too much that I'm aware of) has given a place and a certain degree of common practice to way #2. Right now at least, people are free enough in places like America that they can openly admit to believing differently than what those who follow way #1 want them to. Thus, a friendly, nice sort of Christianity and Judeism and such begins to show up.
That can be a good thing, I think. From something which can be terrible comes instead a kind, loving sort of belief without any of the hatred or closed mindedness. The only harm that I can possibly see coming from it is that it could somehow reinforce the continued existence of way #1, but that doesn't seem to be all that likely. Essentially I think of it as christianity metamorphosing from this monstrous thing into something passive, kind, and really kind of neat in it's own right. It's a shame that not everyone who follows christianity makes that kind of a transition, and instead so many opt to continue the ways of hatred and control.
Then again, I'm an agnostic, not an atheist; I'm not in the business of telling people what to do, only in expressing my own feelings and opinions (which are in no way inherently "right", and I stress that point). I don't think there is a "Truth" I can know for certain because there's just too many unproveable, unanswerable questions. I don't really KNOW anything for certain- to my viewpoint, I can't.
That said, it has been my observation, and the observation of others, that Way #1 has historically tended to engender:
"Excuses" for primal atrocities/hideous crimes and aggressive warlike behavior (see the old testament, Deuteronomy being a prime example)
Horrible dictatorships/supremesist governments such as Nazi Germany (Hitler himself was quite religious- and incidentally, Christian)
Mass murder based on nonsensical claims, paranoia, misdirected hatred, and stirred up crowds, such as the salem witch burnings and Spanish inquisition
"Excuses" for slavery, control, bigotry, and unequal rights (throughout the last several hundred years or even millenia, right through the present day here in America and many other places)
Closed-minded family relationships, parents doing horrible things to their children (my parents are a MILD example of this simply for being unreasonable and controlling and bigoted, and it's soon going to destroy my relationship with them when they learn I'm things they don't want me to be expressly because of their religion combined with their own personal fear. Plenty of parents beat their children for far less, and very, very often those people are aggressively religious.)
You do the math.