No, it is not fair to say that "a missed telegraph pole delivery" was "what caused" World War II. Even if we are willing to give the Joker the benefit of doubt, that he meant "one of the causes", the impact of that one missed delivery is much less significant than The Joker, or the web articles you quoted, imply.
Poincare's decision to invade the Ruhr came at the end of a protracted, many-year battle with Germany over reparations, during which time Germany had defaulted repeatedly on their reparations. This problem was made worse for France by Britain's reluctance to enforce those reparations in the face of German inflation: Britain wanted France to reduce, or at least temporarily delay, those reparation payments, while France considered the issue non-negotiable.
France (and Belgium) had been arguing for the occupation of the Ruhr for much of 1922. One of the payments that Germany was supposed to be making regularly was timber deliveries; their default on one such payment gave the French government an excuse to invade. Poincare, by this point, was just looking for an excuse to force Germany to repay, so the actual event (the missed timber delivery) was almost incidental.
I have not seen anything to indicate what the undelivered timber was to be used for, though France was in the process of rebuilding their infrastructure from the war, and it's entirely possible that the shipment was either intended for, or consisted of, machined telegraph poles.
(Ref: Marks, Sally; "The Myth of Reparations", Central European History, Volume 11, Issue 3.)
Additionally, (at least according to historian Gordon Martel) the invasion itself did not cause Germany's hyperinflation, which had started much earlier, and was mostly the reason why Germany defaulted in the first place. (German currency was so useless, France insisted on payment in real goods; those real goods were needed by Germany for its own industry, and without them, their currency just got worse.)
France also did not maintain its strong position over Germany for very long; France's currency tanked soon afterwards, Poincare subsequently lost power in 1924, and France withdrew in 1925. Poincare's successor was effectively bullied by the British and Americans into giving up much of their owed reparation payments, meaning that Germany arguably came out better after the invasion than they started out.
Germany, in fact, was in relatively good economic condition compared to France, since it suffered less damage from WWI. This is the main reason France was so reluctant to reduce their payments (with less rebuilding needed, France feared Germany would become the dominant European power before anyone else was strong enough to stop them -- which was almost true). German political opposition to the reparations, however, was very real, and existed long before the Ruhr occupation happened. Even if the occupation had never happened, and Germany had gotten its concessions in 1922 instead of 1924, there's no indication that the anti-reparations sentiment (which itself was just one small element of Hitler's rise to power) would have diminished at all.
(Ref: Martel, Gordon; The Origins of the Second World War; http://books.google.com/books?id=3xuZqwfrhRAC)
At best, the occupation may have accelerated events that were already underway, but they certainly were not the cause.
I just noticed this bit from Wikipedia in the question:
In fact, the occupation of the Ruhr by the French ... did more damage to the economy than the reparations payments.
and realized I never addressed it in my answer, but it's addressed in the Martel book pretty well. The occupation of the Ruhr didn't do anything to the German economy per se. However, the German response to that occupation was to implement an official policy of "passive resistance", which included telling most of the factory workers in the area that they were no longer obligated to come to work (because their work would just be handed over to France). That decision did some serious damage to the German economy, and did lead to some anti-Weimar riots, an eventual change in government, and a state of emergency. This was happening during the time that Hitler serving his jail sentence and writing Mein Kampf, so he was undoubtedly influenced by those events. But, it was the actions of the democratic German government, more so than the French actions, that the right-wing parties were rallying against.