To analyze this point further and in an honest way, I think the bigger question is whether religion has, for the last 100 years (or more), been playing a positive or negative role in society? The way I would analyze this question is to look at statistical analysis and what most people consider human rights, and then see how religions infringe on basic human rights. Now anyone that has looked at statistics, or follows my blog, will know that there is no uncertainty in my mind that religion is anything but a positive influence on society. However, regardless of my opinion we can still consider that religion may still be a force for good in society based on its past positive influence. Necessarily this implies that any act or belief that has molded society in a positive way should likewise be adapted in modern day society.
Now this brief analysis I have given above may be a bit hard to accept, or perhaps you don't agree with my analysis, but I think the next example can give more clarity into why I think we can continue this thought. Very recent analysis strongly suggests (proves?) that societies with human sacrifice have allowed our societies to develop in they way they have today.
"Unpalatable as it might be, our results suggest that ritual killing helped humans transition from the small egalitarian groups of our ancestors, to the large stratified societies we live in today."
Now perhaps it can be argued that egalitarian groups are better than large stratified societies, but this negates the reality we live in and as such invalidates any argument coming from that angle. This is particularly true when we consider that religion probably only started to arise when groups of people started to live in groups where they likewise effected the social structure, i.e. not egalitarian.
So here is the conundrum, if you are of the opinion that religion is good for modern society, then by default you have to embrace the idea that human sacrifice is likewise good for modern society.