Jehovah's Witnesses are as humans as anyone else and therefore exposed to the same dangers as everyone else. This time it was their turn to be targeted, and there wasn't any supernatural intervention to spare them from harm. On one hand, it says that they're no different than everyone else; on the other hand it says they're not some special breed.
Nobody deserves to die while gathered peacefully as a community to worship. Then again, I'm sure the question in many people's minds will be: Where was Jehovah? Where was Jesus? Where were the angels? The way the Watchtower spins it, everytime the JWs are engaged in Jehovah's service, they're under special protection from their enemies; yet time and time again that idea is proven false.
Think about the tremendous earthquake that destroyed Lisbon in 1755. It took place on November 1st at 09:00 when the churches were packed with believers attending mass for All Saints Day. Thousands died when the church buildings collapsed over them. Where was God then? That tragedy led many to dare to question their beliefs, like Voltaire, paving the way for modern secularism. Likewise, I'm sure this senseless tragedy will cause many JWs to pause and start thinking too if what they've been taught is truth or vaporware.
My heart goes out to those whose life is forever changed by this tragedy. Nobody deserves to die like this. Nobody deserves the trauma they're going to have to endure for the rest of their lives.