sure, you have a right to insult and cause offence but remember, if you do, you might end up with a knuckle sandwich. Go for it. Its your choice and you live with the consequences.

In other words, if you say my mother wears army boots, I might take this as an offensive remark and defend the dignity of my mother by decking you.

Say something offensive and be prepared for the defense - whatever that might be. You are responsible for your words and deeds. Simple as that.