I would suspect there of other reasons that people use profanity. However I would suspect that the above two reasons sum it up for most part. Indeed, if a person cannot control his tongue, it is probable he cannot control his life either.
On the other hand, there are those that use profanity intentionally. It helps their ego. They think it adds authority to commands or instructions. When calling attention to another persons faults, they think that it helps add emphasis. .The stronger the profanity, the more of them that are strung together, the louder the words, the more emphatic.
Jesus, when he was told that some people were not washing their hands before eating, said that it is not what goes into a man’s mouth that defiles him, but what comes out. With these few words, He tells us that a man defiles himself when he uses profanity, regardless of the reason. By implication the Bible says that when filth pours out of a man’s mouth, then it tells us that what is in his heart is filthy too.
Some lack control. Some do it for their ego. Some use it to profane God’s name. Some do it on purpose and then act as if it was a moment of weakness. To God, it is all worse than not washing our hands.
Because it has it has become so commonplace, people think it’s okay. Fact is, that makes it all the worse.