I have noticed this too. I believe it is a natural progression from the fact that polite conversation amongst these individuals is a lost concept. Every one of them MUST say what is on their mind immediately. No waiting for a pause in the conversation because there is none. It is as if they simply cannot hold a thought in their head for more than a few seconds and form a complete sentence before speaking. No 'buffer' so to speak. If you pause while speaking...for even two seconds...you get interrupted.
Sooooo...they fill the vacuum with whatever vocal noise they can.
Simple, polite, CONversation is becoming a lost art. It has evolved...or devolved...into a room fool of ravens creating cacophony.
Most young men and women, defined loosely for the purposes of this discussion, use vulgarity-laden speech to make themselves sound important or powerful while eschewing those of us who utilize words such as 'eschew' or 'banality.' It's similar to what Robin Williams said in Dead Poet's Society:
So avoid using the word very because its lazy. A man is not very tired, he is exhausted. Dont use very sad, use morose. Language was invented for one reason, boys - to woo women - and, in that endeavor, laziness will not do. It also wont do in your essays.