There are Christians who dishonor God's Name by blaming Him for their poor decisions or for the sins they have committed. When I was pastor of First Baptist in Martinsburg, there was a man about my age who was very active in the church. The reason he gave was God led him to this other woman and wanted him to be happy in life. In addition there are Christians who use words with cruelty. Even good children are capable of visiting cruel words upon others.
Words can indeed hurt .
The problem is that as children grow into adults, they don't outgrow the sad art of hurting, dishonoring with words, but refine it. Misuse of words has implications in many areas of our lives. Invoking lord's Name is serious business. If we don't mean it, isn't this just a plain old lie. Jesus commanded us to avoid swearing in such ways.