Oh, I know I'll have to deal, because segregation is neither an option nor desirable. Language is a living thing, and I can't even control the jargon usage in my own cultural backwaters, let alone the nearby ones. Interestingly, I suspect the usage irritates me particularly because the subcultures are close neighbors. I think you get something like an uncanny valley effect when you get two subcultures that are close but not quite the same, a sort of push-me, pull-you of cognitive dissonance. I have a feeling that something similar drives this complaint about the way American English is infecting British usage.