Yup, it doesn't specify in Law that it has to be directed at an official to constitute OFFINABUS. I have to admit I am a little lenient when it comes to, what I think of, as 'conversational language'. ie, two defenders sorting out an issue between themselves 'cover me Bill, he's too fkin quick to through balls' etc
But if it's getting a bit loud, I'll have a quiet word "Watch the language lads, there's kids around/this is a public park" etc. If it is aggressive, or angry and directed at me or a player then the cards come out. I think swearing has become more a part of 'everyday language' and has to be treated as such and the context needs to be taken into account.
My first game ever as a qualified official saw me on the flag for a one-sided senior league game. The score was at 6-0 to the home team, when I had to flag an away attacker offside - he was through on goal as well - Ref blew it, attacker walks towards me 'I wasn't Lino!" "Yep, just half a yard fella, but you were" As he turns away I get the "Aaaggghhh F### Off!", wasn;t shouted AT me , nor was he looking at me when he said it. Ref heard it and came over to me - "Did he just say what I think he said?" I said, "He did, but in fairness, if I was in his position and 6-0 down after 30 minutes, I would probably be a bit louder and more abusive!" Ref went and had a quiet word with him, obviously told him what I'd said 'cos I got a sheepish thumbs up from him and the game went on.
He did get booked for dissent later in the 2nd half though. lol
(Was so one-sided it was 8-0 at half time, but finished 10-2 in the end)