oh dear oh dear. we're back with the hackneyed clichés of yesteryear. For the avoidance of doubt, it was the Central Powers which killed the men of the BEF, not their own Field Marshall. The German Empire possessed the best and one of the largest armies in the world. It is inconceivable that she could have been defeated without suffering and inflicting mass causalities. Anyone fought Germany 1914-45 suffered mass casualties, in every single theatre. The claim that somehow Britain's position was unique and that therefore this must be Haig's fault is lazy thinking.
Again, for the avoidance of doubt, 1914-18 saw any attacking general having to wrestle with exceptional problems: no portable radios, lack of portable machine guns, superiority of defensive weaponry, huge advances in the technology around artillery, the development of an all arms battle, advances in airpower, abundance of barbed wire etc. The fact that the generals of the British Empire eventually overcame these problems and defeated an exceptional foe without their army collapsing (unlike Italy, Russia, Austria Hungary, France and the Ottoman Empire) suggests that Haig was not quite as culpable as you suggest.