Never had it done to me while flying, but from talking to colleagues, the aircraft windscreen can diffuse the light signal so it is not a pin point anymore, but rather a wide splash of colour. That image in the article (while probably posted for dramatic effect) sounds like what another pilot I've spoken to experienced when a suspected laser was pointed at his cockpit.
Yes, from the pictures it looks like the light diffracts off the glass and fills the cockpit.
The plane moves fast but it's also far away, so the angle it changes by relative to the guy with the pointer is small. To follow it, you wouldn't have to move the tip of the pointer more than (if my rough calculations are right) about a centimeter a second.
Even a split second of that bright flash is enough to make you lose your night vision and leave dancing squiggles all over your retina. Ever had someone's camera flash go off in a dark room? Now imagine that disorientation and loss of vision when you are in charge of several hundred tonnes of metal, plastic and glass containing 200+ souls hurtling towards ground contact.
At that point of the flight, the pilot's eyes are constantly jumping from a methodical scan of internal instruments to the runway and back. Anything that distracts or jeopardises that process can snowball into a big problem.
In many ways, the short term effects of a laser pointer pose a far more serious threat to safety.
