Why?

In four short years, from 1914 to 1918, over 10 million men and women serving in armed forces on fronts around the world were killed, while double that number were wounded, disabled and disfigured; and at least another 7 million civilians lost their lives as well. Most died horrific deaths. But as time passes by we tend to forget, a century later, how many sacrifices were made day after day on both sides of one the most deadly conflicts in human history. Civilized Productions has produced a wonderful choral album, Sacrifice and Solace, which features an octet called the Toronto Valour Ensemble who sang these carefully selected and uniquely composed songs from that era. It is available on CD Baby. The simple translation of the Arabic word "jihad" is struggle.

The Struggle for The Truth

One hundred and one years ago, in 1914, citizens of the world found themselves at war. On August 4, Germany invaded (neutral) Belgium and Britain subsequently declared war on Germany. By doing so, Britain also plunged its Commonwealth allies into the costly fray. Canada, Australia, New Zealand, India and South Africa were automatically committed to delivering men and women to the front and those not enlisting were expected to pay for the troops' training, transportation, equipment and munitions, and hospitalization, as well as food and lodging along the way.
Newspaper editorials were relied on to ensure readers were aware why their sons, brothers, fathers and husbands had volunteered to fight, and possibly to pay the supreme sacrifice in battle. The Austro-Hungarian army was sent to war after the assassination of its empire's heir to the throne, Archduke Franz Ferdinand, to halt radical separatists in the Balkans. Leaders in Russia condemned the aggressive actions of the Germanic states and mobilized its army in defense of Serbia.
Russia's army quickly invaded East Prussia but were defeated at Tannenberg, and in September Germany's likewise advance into France was halted at the Marne and with the war merely a month old the Western Front was a stalemate and would remain a killing zone until the United States declared war on Germany in 1917, ending its policy of neutrality stated by President Woodrow Wilson at the outset of hostilities, similarly at the Eastern Front until the Bolsheviks came to power.
It is believed today, and at the time, that the unprovoked and thus widely publicized sinking of the Lusitania was the reason America reversed its position and began to mobilize its troops. In addition to eventually selling a lot of razors and pens to soldiers heading overseas, the war in general was a boon to corporations, whose owners circling Washington would've certainly lent their vocal support. The Lusitania's cargo included over six million rounds of ammunition (courtesy J.P. Morgan) destined for British and French soldiers, augmenting the 1,200 lives lost off Ireland.
The international finance community was giddy at the prospect of war. On August 3, according to then-US Secretary of State William Jennings Bryan, the French firm of Rothschild Freres cabled to Morgan and Company in New York suggesting the flotation of a loan of $100,000,000 to pay for French purchases of American goods.
On May 27, 1916, President Wilson spoke to the League of Nations and argued that to prevent the recurrence of a similar war a world government was needed. To make the world safe for democracy, nearly a year later, on April 2, 1917, the President asked Congress for a Declaration of War, which was granted on April 6. The United States was now in the war to end war.
It is now known many American families profited from the decision, including the Rockefellers, who were apparently quite eager for the United States to enter World War I, and made far more than $200,000,000 during the conflict. 
Major General Smedley Butler, USMC, criticized war profiteering during World War I in his book, War Is a Racket, stating some companies and corporations increased their earnings and profits by up to 1700% and many willingly sold equipment and supplies to the U.S that had no relevant use in the war effort. "It has been estimated by statisticians and economists and researchers," Butler added, "that the war cost your Uncle Sam $52,000,000,000. Of this sum, $39,000,000,000 was expended in the actual war period. This expenditure yielded $16,000,000,000 in profits."  
War was upon the world and its citizens needed to act accordingly. Men went to the front lines and women to the assembly lines. Newspapers were publishing propaganda as fact and greatly influencing opinion. Notwithstanding the Defense of the Realm Act, introduced a mere four days after war broke out, which restricted criticism of the war effort, to maintain high levels of morale across Britain, editors simply began to demonize Germans in their daily papers, embellishing stories and alleged atrocities, bordering on the hysterical.  
With censorship, British blunders went unreported as did German victories. Nonetheless, some journalists sought to report the truth, whether the shortage of shells or useless (Ross) rifles. The Daily Chronicle's Philip Gibbs and the Daily Mail's Basil Clarke risked the wrath of Lord Kitchener by defying his ban to report from the front line. Gibbs was arrested, warned that if he was caught again he would be shot, and sent back to England, and Clarke, after reporting on the devastation in Ypres, was returned home with a similar warning. 
Even the bloodiest defeat in British history went largely unreported. At the Somme in 1916 - in which Allied troop casualties numbered 600,000 - the battle's disastrous first day was reported as a victory. 
Still at the front, Gibbs defended his actions, claiming that he was attempting to "spare the feelings of men and women, who have sons and husbands fighting in France". He claimed that the truth was reported about the Somme... "apart from the naked realism of horrors and losses, and criticism of the facts." Only later did the public learn of the high casualty toll and the horrific nature of trench warfare, such as the use of poison gas and the effects of shell shock. 
With these appalling conditions in mind, it was no wonder that UK Prime Minister Lloyd George confided to CP Scott, editor of the Manchester Guardian in December 1917: "If people really knew [the truth], the war would be stopped tomorrow. But of course they don't know, and can't know."