The cabin is has more sensitive cargo than the hold. Whereas an explosion or explosive deflageration in the hold is contained in engineered luggage bins, buffer

The cabin is has more sensitive cargo than the hold. Whereas an explosion or explosive deflageration in the hold is contained in engineered luggage bins, buffered with clothing padding, and placed in a random location, in the passenger cabin it could be placed at a specific point. Also, the environmental system pumps to the hold sections can be turned off to cut fresh air to any fire. Comparatively, the notion that some passengers will act meaningfully to put out a fire in the cabin is laughable, it would be a mass panic and everybody and dying. However, with 200g of high explosive, and an aluminium laptop to form an explosively formed penetrator, there is going to be a big hole in the plane no matter where it goes off. Compared to the stuff being used against coalition forces in Iraq a few years ago, no particular technical challenge. So quite worrying.