I too think that the bible can lead some to act with cruelty and/or injustice. The main point of holy scripture is to instruct whoever hears it (or reads it); that is one of the reasons that saint Paul wrote that "All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: That the man of God may be perfect, thoroughly furnished unto all good works.". Holy scripture is not a law to be imposed on people regardless of their religious views. It is instruction in righteousness for those who have faith and are willing to allow holy scripture to shape their conscience and inform their lives. If one tries to make the scriptures into the law of the land or the rules of a chat forum it seems to me that inevitably somebody will treat somebody else badly on the pretext that the bible told them to.
We are in agreement on those who use Scripture to justify being cruel. Though I am wary of saying the Bible is what leads them to such acts. This is an individual problem, and we know ideology and prejudice is shaped by many factors. People will always treat others unfairly or cruelly, that's the downside of living in a fallen world. We cannot let the evil of some taint our view of the rest. Of course we have those who spew vitriol while themselves leading lives of iniquity; not hard to spot a hypocrite - don't let those hinder the unshakable truth that all true followers should know.
We are urged as Christians to instruct, reprove and help others. And I do believe as Christians it is imperative we keep to the Word of God. This being said, I do not force my beliefs on unbelievers, but will certainly voice to fellow brothers and sisters (in Christ) if in error. it is our responsibility to never condone sin, and letting a brother believe they are not sinning, is very dangerous ground.
The Bible never tells a believer to treat another unfairly, cruelly or with partiality. What it does tell us is to follow in faith: spreading the Gospel of Salvation, and adhering to the Word in all facets of life. In my thoughts and actions, at the fore always is how I will answer to God.
I can easily condemn actions of a brother and love them all the same. God is testament enough to this. Any obstacles we face in this world are of the devil. How we handle them is important - remembering always, we answer to God not the world.