1: The cartoon is suggesting there will be another war in 21 years time,when the weeping child will have grown up and be old enough to fight in the army.This is because the Treaty bo Versailles has been poorly thought out,and was instead sowing the seeds for the next war.
2: Britain wanted a rapid economic recovery for Germany after the war.As Germany had the largest European economy pre WW1, the quicker it recovered,the quicker the rest of the economies in Europe would recover. Britain was a trading nation, so it needed countries in Europe with strong economies to trade with.The French insistence on Reparations meant there could be no rapid recovery in the German economy, so rapid recovery of Europe's economy as a whole. This would have a detrimental effect on the British economy.
France wanted to cripple Germany economically and militarily to the extent that it couldn't be a threat to France for the foreseeable future.However, reparations, territorial losses, and restrictions on the German military all fell short of what the French originally demanded.
USA, in the shape of Wilson, was upset his Fourteen Points weren't adopted across the board. However, in truth many of them were unrealistic - for example, Britain was NEVER going to agree to Point 2 'Freedom of the Seas in Peace and Wartime.' Further, if Wilson thought that Britain and France, having done most of the fighting and dying in WW1 were going to sit back and let America, who hadn't even joined the war until well into 1917, dictate the peace treaty, he was delusional.
Germany was unhappy because they thought the Treaty was far too harsh and unfair, not just punishing them but humiliating Germany. They expected the peace treaty to be based on Wilson's Fourteen Points. However, this was a dream; they were given no guarantees about the terms of a peace treaty when they signed the Armistice in November 1918, so couldn't expect some sudden change of heart by the British and French at the Paris Peace Conference.