We got called into school by our son's English teacher. During the poetry module, my son had gotten a bit frustrated and said, "Who the heck is ever going to use fucking poetry in real life?"
"While I felt he had raised an excellent question", his English teacher said, "I didn't agree with the way the point was expressed. I'm sure you see my difficulty."
We did. And we appreciated his good humor.
We had a carefully considered discussion with our son about respect, and appropriate language.
Expulsion is a very blunt tool.