> Some of the initial footage shows such a device going off while innocent bystanders remain unharmed.
This is anecdotal and misleading. There are reports of civilians maimed including the murder of a child. This is entirely plausible due to the indiscriminate nature of these bombs with respect to immediate bystanders.
If an enemy had set off thousands of small bombs in American supermarkets and homes, maiming thousands of whoever was nearby and killing children, we would undoubtedly call it a mass terrorist attack.