(And it's just an opinion section, it's not some conclusive investigation.)
You don't treat dead people in a hospital during a war. They don't get taken to hospital. You treat people "just hurt enough" to require surgery, but not so much that they definitely won't make it with or without surgery...
... such as single gunshot wounds to the head, which are surprisingly non-fatal. There's many(!) stories of people trying to kill themselves by shooting themselves in the head and failing.
The stories told by the people in the article are anecdotes by a select group with a strongly statistically biased view of the world on top of a personal bias against a literal enemy at war with them.
They're probably not wrong and they're probably not lying, they just can't see the whole picture and can't possibly know what an Israeli soldier is thinking our doing at the front line far from the hospital.
This just doesn't make any sense.
On one hand, it's trivially correct in that no forensic information can ever tell us anything about the intent of the person who fired the bullet.
But otherwise, what you're saying just doesn't hold up to basic common sense. First, "All bullets lodged in the body" definitely do not look "the same" -- some are fragmented or marked in ways that otherwise show signs of having passed through something besides human flesh (more suggestive of an indirect hit) while others are not (suggesting a direct hit).
The circumstances of the entrance would can also say something about the bullet's approximate velocity when it entered the body, and direction of fire. Finally, the location of the wound is itself very important - a disproportionate number of people with gunshot wounds to the head tends to suggest that, well, that's where whoever was firing at them was aiming at.
Such indications may not be sufficient to determine conclusively that someone was sniped. But they do shift the overall balance of evidence, and require us to weight our probabilties for any such interpretations of what happened accordingly (in the context of other available evidence, of course).
It isn't as if the condition of the bullet and the circumstances of the wound provide no signal at all in this regard, as you're suggesting.