The problem is that if Western governments were to play the waiting game before commenting on this incident, there'd be an information vacuum that would be filled with Kremlin propaganda. We've already seen how easily the gullible are fooled by this misinformation with Georgia, Syria and Crimea, and how that can affect actions taken (or not). We all knew that the "armed gunmen" who appeared on the streets of Simferopol were Russian soldiers, but because the Kremlin constantly denied it there was uncertainty affecting the western response. I'm sorry to say we've been reduced to Kremlin tactics of getting your message in first and getting it in loud. I'd like to think that's a lot easier if you have the weight of evidence behind you if not a smoking gun.
You can simply comment with we will wait to see the causation. You don't have to start making stuff up.