"But we Christians believe that humans are basically sinful..."
I really need to stop listening to so much Christian radio news. But it's addicting I tell ya! Today they were interviewing (starts at 1:20) a guy who wrote about about the indisputable fact that violence has been on a massive decrease for the last millennium (e.g. 99% drop in the last 100 years for instance). It's pretty subtle (but priceless) to hear the confusion in the voice of the interviewer as he tried to reconcile this fact with the notion that man is inherently sinful.
I'm sure it has nothing to do with the relentless march of secularism. Probably a trick of Satan!