Lots of things can temporarily blind someone. A hand-held mirror, a flashlight in the dark, high-beams from oncoming traffic... Are these "weapons" as well?
And causing permanent blindness with a laser pointer at long range is a far-fetched idea.
You my think it is a far fetched idea. But if you understood the simple physics behind the power that these laser pointers can generate, you would know that they CAN permanently burn the retina.
But even so, how long do you want your pilot to be blinded while making a landing?
Per OSHA Regulations (Standards - 29 CFR)
Nonionizing radiation. - 1926.54
...Employees shall not be exposed to light intensities above:
(j)(1) Direct staring: 1 micro-watt per square centimeter;
(j)(2) Incidental observing: 1 milliwatt per square centimeter;
(j)(3) Diffused reflected light: 2 1/2 watts per square centimeter
These 100mW range green lasers can generate powers far greater than these standards. Further, if you don't believe me, consider the following: http://vision.about.com/od/eyesafety/a/laserpointereye.htm.
Note this section of the article:
Mayo Clinic ophthalmologists made the discovery after exposing a diseased eye about to be surgically removed to green laser pointer light. Archives of Ophthalmology (May 2005) reported findings that green laser light damaged pigmented cells within the retina, the inner layer of the back of the eye where images are processed. Damage occurs with as little as 60 seconds of exposure.