I think sometimes arse is used in a sort of ironic sounding way here.
In general though, outside of this one, a lot of things that somes get described as British use turn out to be things that I would also say. Sometimes there are regional differences in the US, or sonetimes it might even vary with the individual. The patterns of who says what aren't always so neat and organized as "this is always American, this is always British."
I myself have one parent who was born in England and immigrated here fairly young, and I sometimes wonder if or assume that's a factor for me.
In general though, outside of this one, a lot of things that somes get described as British use turn out to be things that I would also say. Sometimes there are regional differences in the US, or sonetimes it might even vary with the individual. The patterns of who says what aren't always so neat and organized as "this is always American, this is always British."
I myself have one parent who was born in England and immigrated here fairly young, and I sometimes wonder if or assume that's a factor for me.