No one on Earth except Sheldon Cooper would ever possibly say that, and even he would find that awkward phrasing because coitusly is not a real word. People who say the dialogue sounded awkward and out of place now actually think replacing it with "That was so coitously cool" would work better?
And how is that any different in terms of dealing with a child? If you're uncomfortable talking to your child about sex, you now have to explain what that means. A child can learn that it's not appropriate to go around shouting the f-word in school, but they don't know the rules when it comes to this because no one uses it. Also, coitus only has one meaning, whereas the f-word has many uses, including as an expression of surprise and wonder like it was used in the episode.
The grounds would have been, be courteous to others who might consider it offensive.
