By that argument "dickhead" is just a britishism meaning "unreasonable person" and just as appropriate.

I mean yes, yes it is, but thats clearly a pejorative, where as "i'm only here because of you two dickheads" isnt

If you upgrade it to "you two fucks" it still probably isnt.

"you two caaaaaaants", you would need to test if they are from glasgow or parts of london/essex