Because when man reads somenthing they don't like they say it means something else and poof a denomination is born. When someone else reads something they don't agree with they say it doesn't matter anymore and poof another church is born. And some are just misled by the devil and poof another religion is born. but the bible says it's not up for private interpretation. It has only one correct interpretation. If you can read from beginning to end and make it all fit without contradiction then you are interpreting it correctly. Easy beliveism contradicts, trinity contradicts,legalism contradicts, but Jesus is the only one true God and Acts 2:38 does not cotradict.
Because God hands people over to believe a lie....and because there's more than one stage of development to bearing the fruit of faith. The seed of truth can grow in hostile soil if given the proper conditions....but it may need to be transplanted before it can truly bear the righteous fruit of faith.
Had this thought recently: Balance is critical to tight-rope walkers. That's what believers are! Scripture says that the way is strait and narrow - perfect analogy of that "strait and narrow way" is found in the tight-rope! So, I reckon it's real important to maintain a proper balance between spirituality and reality. That's not to say that spirituality is not reality....it's just that we must understand that we are merely earthen vessels which contain a heavenly gift. We are not heavenly beings yet. We do not yet see all things under our feet. But, we do see Jesus!