The problem with all religions is simple - people. People make religion hard work, and they use it to justify oppressing their fellow man.
For instance, Christianity's basic message is simple - be good to your fellow man, and if you do, you'll be happier. It is also VERY clear in the Bible, in Jesus's words and elsewhere, that if you want to have a relationship with God you can, and you dont need anyone else's permission, or approval, and NOONE can cut you off from this except yourself.
Unfortunately this is not what the major organised Christian religions preach - excommunication for instance - the idea that the Church can bar you from heaven - TOTALLY unbiblical.
Romans 8:38-39
38 For I am convinced that neither death nor life, neither angels nor demons, neither the present nor the future, nor any powers,neither height nor depth, nor anything else in all creation, will be able to separate us from the love of God that is in Christ Jesus our Lord.
That's pretty bloody clear to me.
And as for the institutional abuse of children, especially justified by religion, this angers me more than I can say. The perpetrators should be exposed and dealt with no matter who they are and to do it in the name of God, well if He does exist I dont think He will be happy with them:
Matthew 18:6
6 “If anyone causes one of these little ones—those who believe in me—to stumble, it would be better for them to have a large millstone hung around their neck and to be drowned in the depths of the sea.
These are the issues I have with organised religion.
That said, I do not believe that if we got rid of them we'd all suddenly be living in some humanist utopia. Human nature is human nature, and people would simply find other ways and excuses to oppress others.
There is a lot said about Islamic extremists and yes, some of what they do is justified by twisting scriptures out of context, but a lot I think is simply to do with them being young men, they want to feel special, they want adrenalin and they want to get laid.
Just my tuppence worth, I would not want to fall out with anyone here over it.