Well on your list of possible words used, I think its the inference that is profane if any of those words were used, because all of the words are colloquial synonyms for words that are generally perceived to be on the list of 7 profane words that were the issue of the FCC brouhaha way back when Carlin did his piece on the subject. Certainly none of the "7 profane" words would be tolerated in school, so perhaps because there really isn't an arguably genial or non-profane intent behind the use of the words you provided, the school's ambiguous rule as to profanity is based upon the inference, not the spelling or "root word" so to speak. Interesting topic, hope the kid doesn't end up hosed and that you can save his sorry little ass...