Apropos of nothing,
I live in an area with a relatively high Asian population. With a few exceptions who think they're Tim Westwood, most speak English with a Lancashire accent. It's what I've grown up hearing and it sounds 'normal' to my ears.
I was in South Wales a few years ago, went into a corner shop and, true to stereotype, it was run by an Asian bloke. When he spoke he had a thick Valleys accent. It surprised me for a moment, because I was subconsciously expecting him to sound like me.
I'm not sure where I'm going with this, other than I guess that accents are heavily influenced by environment. You speak like your family, your peers, your geography.
There's a difference, I think, between a natural accent and an affected one. I've no idea in the OP's case whether or not the lads were putting on an accent to sound 'cool,' but there's every chance that they speak like that because the people around them do also. Maybe.
TBH, I have a much bigger issue with people typing like retards.