First of all it should be clarified these are casualty figures for the British portion of the front, not the entire front. The English weren't losing that many officers that they outnumbered total German casualties 5:2. You'll also notice they didn't just lose more officers they generally lost more men as a whole; there is a reason for this!

While there is certainly a lot of mumbo jumbo we can go into and lots of speculation there is one simple fact that we need to consider that makes a lot of things clear: The British were compelled, from the end of the "Race to the Sea" in October 1914 to November 1918 to maintain an aggressive stance while the Germans did not. Another thing to consider is the fact that, in the retreat after the Marne, the Germans had the option of digging in wherever they wished -- they were hundreds of miles deep in enemy territory so they were willing to give up a few dozen miles if it meant getting a ridge or something that gave them a distinct advantage.

So the British tended to be noticeably downhill from the Germans (thus having to attack 'upward', an inherent disadvantage) while also having to constantly attack. Why did they have to constantly attack? One look at a map says it all. The British line would extend North/South from roughly Ypres to Peronne and would extend laterally to the sea. As you can see the G.H.Q. was located smack dab in the 'middle' of the front near the sea in Montreuil. When you look at this map something becomes perfectly apparent: the British can be utterly screwed if the Germans break through. If the Germans force a concentrated offensive in the Southern region of the front and succeed they will, immediately, separate the French and British lines. Further, if the Germans pushed inland, the British would be in a Dunkirk-esque situation where they were totally surrounded and had their backs to the sea.

They were completely and utterly terrified of this happening and thus, from the beginning, maintained an offensive stance. If they never allowed the Germans to take the initiative and let the Germans perform the offensive (as they were the ones always doing the offensives) they wouldn't need to worry about a surprise German attack. Basically they'd be losing more men but they'd also maintain operational tempo while the Germans would be the ones reacting. This is also why the majority of British attacks took place on the 'ends' of their front. The Somme took place roughly around Peronne and Ypres/Passchendaele was at the Ypres salient up at the top. The 'ends' were the strategically important places as it's where the lines met up and it allowed cooperation between the two but also the potential to split them up.

This is mostly taking reference to Martin Middlebrook's "The First Day on the Somme" but also Paddy Griffith's "Battle Tactics of the Western Front: The British Army`s Art of Attack, 1916-18" for a more military theory perspective of things.

One reason may be that the British army expected its junior officers to lead the nightly patrols into no man's land, where the German and other armies would leave that job to NCOs.(Perhaps this was due in part to the relatively fewer number of officers in the German army as mentioned by /u/textandtrowel). That was, obviously, a high-risk occupation..

Source- John Stempel "Six Weeks- The Short and Gallant Life of the British Officer in the First World War" (2010).