It's a cop out and weak refereeing.
That's the first time I've ever been accused of that! Usually teams ask not to have me any more because they think I'm too strict! I must let them know that there's someone even stricter!
As Alex says, I consider unacceptable language - which does not necessarily mean foul language, but also is not so bad as to require immediate dismissal - to be 'acting in a manner which shows a lack of respect for the game' as listed in the USB offences at the back of the LOTG, and this is the opinion of the referee. When I caution a player for this it is rarely a shock because I've usually spoken to him before. I belong to the "no surprises" school of refereeing.
Round here, if I sent off everyone who used bad language every time I would struggle to finish games, simply because no one else would be doing it and so it would come as a surprise to the players. I would therefore be sending off several other players after the initial one simply because they didn't accept that what he said was so bad. I send off enough without resorting to that - it would be like shooting fish in a barrel!
At our branch we tell newly qualified referees that even though they don't always have to dismiss players for language they should never ignore it. We also tell them that most cautions will be for USB, which covers just about everything when they can't decide what other category it's in.
As I said before, my supply league was specifically told by the FA that we must not dismiss players every time they used foul language regardless of the circumstances. When we had that interpretation on our league we had problems because when our teams played in FA competitions against teams from other leagues the outsiders were swearing as normal, so our players either got fed up with the inconsistency or else joined in. Then next week when they were back in the league they had issues with discipline again. This was obviously unfair, and so could not be continued.
Unfortunately, with the best will in the world this will not change. There are too many who do not see an issue with bad language and will therefore do nothing. This includes a lot of "serious" referees, never mind those of us who fit into the category of LWRs. Accusing someone of copping out and being weak for offering a potential way to deal with bad language without spoiling the game is pointless. When assessing I suggest Referees set themselves manageable targets, and when they achieve that one, then set another.
Setting a target that every referee dismisses every player who swears is not achievable. There is more likely to be a consensus that we can caution players for language than that we must dismiss every one who does. This should therefore be the target for now. Maybe if everyone does this then we will be able to enforce the Law even more rigidly. However, we all know that won't happen.
I know that as an assessor I should enforce the Laws rigidly when I am refereeing, and I honestly do. I have had comments from people I've assessed who've subsequently watched / lined for me that I referee exactly as I suggest they do in my report, which I consider high praise. However, industrial language is a fact of life these days and a one man crusade will not stop it. I would rather offer an easier and more acceptable option to a) ignoring it, or b) instant dismissal. The game is not about me, no matter how much I would like it to be!