People might say the two sisters were stupid and got killed for being there. Their own fault.

Partly true. A walking safari viewing elephants can be dangerous. Walking safaris are popular for game viewing. I've never done one. But have thought about it. As a hunter I've done it of course while hunting as we all have.

An advantage is carrying ones own rifle. Really important if the guides or PHAs run away. I've heard of that again just recently.

And the "guides", the PHs being probably far more competent.

I wonder about the "injured" or wounded elephant cow in the attack. How competent was the guide in shooting elephants. An "injured"/wounded elephant escaped. Of course anyone can make a mistake or the circumstances create it. However I would have thought the armed guide would be right beside the two sisters.

Guides have lesser qualification skills compared to a DG PH.

I've had a Zambezi River guide, an out of work PH, who I definitely would not want as a DG PH.

Game viewing tourist safaris aren't stupid. They represent an income stream for parks and a legitimate activity for wildlife interest tourism. Dangerous game is called dangerous for a reason. Sometimes no matter what precautions are taken, unfortunate results can happen.