IT’S NOT ABOUT SWEARING
Because most religious people put a high value on using clean language, they do not use four letter words — at least not in public. They would especially avoid using Jesus’ name or God’s name in a way that would be offensive to other religious people. And if they can do this, they congratulate themselves for being obedient to the third commandment. 

Not swearing is considered to be a mark of righteousness. Using only clean language when others are listening  is an unwritten religious rule in a system of religious rules. People who observe this rule take pride in their righteousness and earn praise from fellow religionists. Using only acceptable, clean language is a way of making a good name for themselves

People who have a habit of using Jesus’ name and God’s name in an offensive, non-religious way would eventually be called heretics. They will be unwelcome at religious gatherings where only clean, religious language is allowed. 

Using clean language seems reasonable and right according to man’s religious rules which are based on a wrong understanding of the Third Commandment. The clean language rule disagrees with God’s habit of judging the heart — not the external person.  The truth that religious people fail to understand is that the so-called “Third Commandment” is not about using the literal names of Jesus and God in speech. It is much more complex and spiritual.

See this link for understanding of what God means when he warns against taking his name in vain.