You're fooling yourself if you think humanity would be any less violent without religion. If there's one thing I've learned from watching South Part (Science be praised! lulz ), it's that we will always have reason to fight and murder in the name of something greater than us, whether it be god or simply our ideals. Sure many religionists use their faith as a crutch, but some people just aren't as strong-willed as you are and really need that crutch to hold themselves up. If it wasn't some god doing it, it would be something else-- and really, who are you to judge what avenues we use as human beings to provide hope and comfort in our lives? Would you take away a crippled man's wheelchair because you feel he's perfectly capable of getting around without it, because you think you know what's best for him?
I never claimed humanity would be less violent. We don't know. I think there is definitely the chance that some would not take a godless existence well and act out, be selfish, and commit crimes. Or even if god wasn't a factor at all, for many it goes back to the gene and doing anything to survive.
On the other hand, it can't be ignored how much we are holding ourselves back as a species, believing things that aren't true. Also, many people deprive or hold themselves back in life in the name of god, believing that a hard life today is okay because they'll get a heaven for eternity. Lastly, stopping all of the crimes done in the name of religion, both small and big, shouldn't be seen as a mute point because it's assumed or feared that something might replace those crimes.
As far as saying an able-bodied man should be allowed his wheelchair, I have some empathy and then I don't. In theory, I can empathize with the concept, because life can be hard and sometimes those coping mechanisms are necessary. In the long-term, though, it may be making the person weak and altering their quality of life. If they are in a relationship, it can be very damaging against another person for one to have certain "crutches".
As for speaking "nicely", it has to be kept in mind that seemingly blunt-looking words may be read in a tone that is much higher than the author intended. Regardless, in most cases I don't think people should feel that they should have to sugar-coat their words. I don't go around directly calling a specific person an idiot or anything like that (which I've seen plenty of around this forum).