I am not sure they are used as a 'vehicle' as such.
Soaps do need to be rooted partially in reality in order to strike a chord with their audiences.
Add to that the need for fictional drama to maintain interest, and there is inevitably going to be an overlap with issues in society, because for soap characters not to be involved would distance them from reality to an inacceptable level.
I think soaps have always had a moral core, and more often than not, the consequences of bad behaviour are played out as storylines unfold.
Similarly, issues of loss and tragedy make good drama, but do reflect life for viewers as well.