I find it very difficult to understand the difference between "du fait que", "puisque que", "parce que" and "depuis que". I thought "depuis que" meant since (in time) and not "since" as in because. Guess I'm wrong?
In this sentence, "since" is clearly a matter of time, if you refer to the tense of the verb (present perfect).
So in this instance "since" would translate to "depuis que" because "have been" refers to a point in time?