"Blessed are the merciful"

Why are so many Christians so calloused? I am never suggesting compromising on biblical truths (indeed, Jesus on occasion spoke sharply to his disciples and others) , but aren't we all brothers and sisters in Christ? and if someone isn't yet a follower of Jesus that is even more reason to show them God's mercy by being merciful to them. Not to mention that so many people are stuck in their own interpretations of the bible that they are closed to the whisperings of the Holy Spirit and to growing in knowledge of God's word.

I guess I am just thinking aloud really. It can be confusing sometimes to know where to draw the line between being true to the Bible and trying to see another Christians viewpoint. Any comments on my thoughts are greatly appreciated.