That's ludicrous! Given that, AIUI, the filtering is done at the behest of the company that handles the site's credit card payments, is there no alternative - slightly saner - list of banned words that the said company could be persuaded to let the site use? Alternatively, is there no alternative company that the site could switch to using for processing its credit card payments?
It seems to make no sense at all that one can't use words here that would be perfectly acceptable on F*a*c*ebook or Twitter, or indeed almost anywhere else on the Web. (Apparently F*a*c*ebook is a banned word!)