Perhaps the best visualization of what the issue is, comes from Vagelis Karmiros who has collated all the recent MH-17 flight paths as tracked by Flightaware and shows that while all ten most recent paths pass safely well south of the Donetsk region, and cross the zone above the Sea of Azov, it was only today's tragic flight that passed straight overhead Donetsk.
Thank-you! This is what I wanted to see.