I don't think its ambulance chasing at all -being in the back of a plane doing something unexpected can be terrifying. I've had two incidents in my life - first was in Basra, in the back of a Merlin where clearly something unpleasant was going on outside, involving a lot of diving around the sky at night and flares going off (and I flew often enough to understand difference between routine flares and normal jogging and sense that something wasn't right). This left me shaken, not due to the crew, but the circumstances and not knowing what was going on.
Second one was last year on a Virgin aircraft flying NYC - LHR, where without warning mid atlantic, during a meal service we descended so severely for about 30 seconds that we had to hold on to the cabin crew to stop them flying down the aisles. No explanation offered after we levelled out, nor seatbelt signs on. It was genuinely frightening as the crew themselves began to look and sound worried.
In the latter circumstance, for several months after, and to a degree even now, I found myself feeling very uncomfortable when it felt as if the plane was doing 'something it shouldnt'.
So, yes, I can easily sympathise with those who by all accounts had a deeply unpleasant experience. Whether they should sue or not is a different issue.