The bombing of Lybia came at the behest of France and the UK mainly. France even was conducted the large majority of the bombing. The Syrian conflict was underway for almost two years before the US armed any of the rebels. This after Assad famously crossed the Presidents "red line." The President obviously did not want to get involved, but it happened. Reading some foreign media and you would think the US started the whole thing, same with Lybia.
You are right in assuming that the US did not specifically start the Syrian conflict, if, by "start," we mean intentionally instigate it. (The conflict is the result of numerous factors, and is not explainable by reducing its origins simply to "the US caused it.") The US did, however, try to take advantage of a bad situation there, an attempt that only aggravated the crisis. We saw an opportunity, and once we inserted ourselves into the conflict, we only backed ourselves and others already involved further into a corner.
What I think many people around the globe, specifically in Europe, confuse for "US instigation" of the Syrian conflict is the fact that our unadvised invasion of Iraq set the wheels in motion for the Syrian conflict, or at least accelerated its inevitability (honestly, much of what we're witnessing today in the Middle East was probably inevitable; we just accelerated the timeline). So, in this sense, they're technically correct, but just not in the sense that they think they are.
Speaking of blame for the conflict and the simple, reductive "black-and-white" narratives that we often use in assigning blame, it has baffled me that more blame has not been apportioned to Russia for instigating the conflict. Assad was Russia's last remaining "ally" in the Middle East (Iran is debatable). Did Putin have no interest in or need for quelling the violence, both Assad's and the opposition's, either diplomatically or with force before things got completely out of hand? No one would give the US such a pass.
