While I agree that the prior comment was condescending and not very helpful, I think the key arguments (already put forward elsewhere in this discussion) against the "they have good intel" argument still stand and so far have not been plausibly refuted:

a) I would assume the U.S. would share such intelligence at least with their allies. So why has no other country except the U.K. implemented similar measures? Do they all willingly risk their citizens lives?

b) Why only flights from certain countries (until now Middle East, starting now apparently also Europe)? Don't you think a plane bomber from the Middle East would just put their bomb-infused laptop into the cargo hold, fly to the U.S. and then take it out there and into carry-on on a domestic flight?

The counterargument to b) is that the countries on the ban list have lower carry-on security measures in place than the countries not on the list. I personally would doubt this, especially given the variety of countries not affected by the ban, but I don't have hard data on that.