Can you explain the 'no electronics in the airplane cabin on flights from the middle east' policy to me?

TSA announced that certain electronics – basically anything larger than a phone – can no longer be carried in the cabin of the plane,. It has to be carried in luggage beneath the plane.

I guess that the theory is that the electronic <thing> might explode.

That’s where I am confused. If it’s a timer or altimeter-based weapon, couldn’t it explode and cause just as much damage in the baggage compartment?

Or are they worried about humans triggering explosives?

Or is this another way to discourage muslims from coming to the US?