I believe that far from creating an atmosphere of enjoyment, drinking in these workplaces causes problems. Even if it is an after-work dinner, it is still the place where colleagues are, and an event organised by the company. It is not the same as going out with colleagues to a bar.
I'm with you here; I see these events as work and whilst I'm ok to relax a little (for me) there's still standards to uphold. Many probably don't agree with me though, or don't have the discipline to abstain. Each to their own I suppose, but trying to pressure someone I to drinking...what a fucken dumb ass.
Not all people have the same limits. But everyone is who they are and will figure out how to carry their heavy load.