Namely that everybody knows what you mean so you can’t use the disguised version in an untargeted mailing (or presumably any other paid-for communication) as everyone knows what it means (clearly true) and some people might find it ‘irrelevant, gratuitous and offensive.’
Well good for them. The object of the ASA’s ire is a marketing outfit called The Fuel Agency which sent out a mailing to 1,000 people claiming “I f**king love you’ hoping that ‘you might f**king love us.’ Two people complained to the ASA (quite a lot actually, from a limited edition mailshot).
We use fuck the whole time time these days of course, even your correspondent has been known to utter the word when something really disastrous happens, like he can’t find his Oyster card.
But someone has to try to stop these marketing types running amok in public and in its 30 years or so of of existence the ASA has done a remarkably fine job of it.