Keith writes

1. Britain had little choice but to stand against the invading German armies.

Even if we accept that as of 1914 (as we must for France), politics had (theoretically) had ample opportunities to achieve a more stable peace in the decades before. This applies to the governments of all other major powers, as has been written by many posters above. Historians can try to find some causalities, but for the purposes of this thread, all we have to know is that that way of doing politics must be thoroughly condemned for out times, and therefore must not be glorified in retrospect.

2. The people understood and responded by volunteering.

As we have seen, historians in hindsight do not know what exactly was going on, so how should "the people" have known, including soldiers? Without the Internet, they had to rely on their newspapers and official propaganda. Many were convinced and volunteered wholeheartedly, many others were coerced. Some wanted national glory - then considered more valid a cause than it is nowadays -, others were moved by stories of the enemy's atrocities (which the propagandists usually needed not invent, just select).

Also, soldiers in particular tend to take pride in doing what their leaders say, and to be happy to be praised by their governments. Once the war has been entered, civilians usually suspend any criticism as well - reactivating it afterwards is not always easy.

Exactly the same applies to Germany and Austria. Quite a number of former anti-monarchists and prominent moralists suddenly rallied behind the kaisers and their governments. Efficient propaganda, not a good cause.

3. Despite some disasters as the new warfare was mastered, the British Army was well led.

Compared with what? Most leaders would not waste their soldiers' lives out of sheer fun, but winning the war was considered worth all sacrifices. Technically good leadership does / would not make the cause any better.