This is not a joking matter.
Such a weapon would need to be focussed, and would require a significant power source. Moreover, it would be a sitting duck for an attack by stand-off missile. Only a well-protected agent/agency (police, military) could use such a weapon effectively for any extended length of time. Hence the idea that terrorists are going to get any mileage out of it doesn't make a lot of sense to me.
If we don't laugh at them the terrorists will have won.