It’s puzzled me a lot too! A forkie I used to work with effed all the time. Every effing other effing word, with an effing eff in words over two effing syllaeffingbles. (He didn’t know many of those though). He asked me why I didn’t swear. I told him it was a waste of breath. It took him twice as long to say something as me.
So of course his use of the word is meaningless. Compared to, say, a religious person who drops a rock on his foot and says “darn!”. That’s more of a swear word than a day’s worth of the forkie’s effs.
And this is indeed enshrined in the law. A lay magistrate mate had a case where the police had followed a man onto his property. Before they took any action, he told them to eff off. The clerk to the court advised the board (of three lay people) that for a person of his socio-economic background, such a phrase could be considered as a legitimate request to leave his property, after which anyone refusing to do so must be considered trespassers.
