the discussion now is going forward, not the past.
airlines now know there is a potential risk, and must assess it accordingly.
relying solely on external sources, and not erring on the side of caution may not be the optimal going forward. BA has said each airline must do it's own risk assessment.
i maintain airlines flying over Ukraine were not wise, although a court may later prove me wrong. hindsight? well... most lay people weren't looking to analyse the situation until MH17 occurred. but that doesn't mean someone specifically tasked with the risk assessment wouldn't have been able to see that something may not have been as safe as it might have been.
if someone had raised the discussion of two aircraft being shot down in a place where airlines were flying, I think many would have thought 'why would anyone fly there?'. Airlines, who's primary focus should be on safety, should have looked at that. Airspace closed below level 32000? what if you needed to descend due to loss of cabin pressure? what if you needed an emergency landing? Ukraine approved it's airspace? but did the rebels?
there may be nothing wrong with hindsight, if the people involved were not on the ball. sometimes more heads are better than one. That's why we have inquiries, to determine the facts and perhaps ultimately decide that the actions at the time were or were not prudent.
Going forward I think airlines should be more cautious. Safety before satay.