I meant to reply to this last but retied from the garden one of the walking wounded
"banter"
To a degree, this has always been been a part of some performers performance - (others chose to chuck-up over the front row of the audience) - I never remember foul-mouthedness, but bawdy innuendo is part of out traditions
What did disturb me was when the clubs became refuges for fourth rate would-be comedians not good enough to make in on the Working-mans club scene - robust (I refuse to call dictionary-based words that have been part of our vocabulary, "foul") language became a part of this, but, after 'Lady Chatterly' that was general - the language was out in the open, whereas, previously society had driven it underground
You only need to look into what was happening in real life in stiff-necked Victorian Society where socail reformers were using the children they were 'saving' prostitutes and to condemn a child to the care of the church was to plunge him or hear into a woerld of institutionalised violence and debauchery - that continued until it was finally exposed in the latter half of the twentieth century and is not yet fully understood

I served the first five years of my working life on the Liverpool docks, where such language was almost obligatory if you ere to be fully accepted; I wouldn't use it at home because my parents had been conditioned by the church not to use it, but they were both aawre of it and both, in their different ways, even respected
My mother was a gentle, humourous and totally inoffensive woman who, when you asked what was for dinner, would reply when under pressure, "Cow's cock and hairy bacon"
When I took my first teetering steps as a singer she heard me practicing and said, "If you were singing for shit, you would't get the smell of it" (she lived long enough (just) to quite like it and come out to listen to me)
My dad adored and even studied the rich variation of our language (he was a navvy who spent his life where the air was permanently blue)
It was he who pointed out the meaning and significance of 'Ophelia's "nothing"'

This 'foul' language is a part of what we are and where we have been - I believe it only becomes 'bad' when it is used unnecessarily gratuitously, or when it is used to insult and demean - 'shocking' people is part of our culture, particularly through humour (It's well worth reading what Gershon Legman had to say about it - or working your way through he two Vance Randolph books)

That it is 'always with us' was driven home to me one night in our local pub in Kirkby (Liverpool) when I sat near to a middle-aged couple of regulars - usually quiet and reserved - and particularly 'well-spoken'
They were quietly having a blazind domestic row under their breaths, when suddenly she said audibly enough for everyone to hear, "All you ever think of is your belly and what hangs under it" - I don't think you can beat that as a put-down
Jim