Are you saying that since just about any flight can be considered a terrorist target, that we cancel all of them?
No, not at all! And of course, any flight
could be considered a terrorist target.
In any case it's not the sky marshalls that I'm saying necessarily represent the danger, it's the mere fact that they are required to be present that I would have thought would cause a worry.
As I understand it, not every flight will have them as there won't be nearly enough for this, at least for the foreseeable future (or at least I would hope that the training standards required would be so high that not just anyone who can fire a weapon is qualified) So it's a fair assumption that if they are deployed on your flight, it's because the perceived risk of a terrorist incident is higher than on a non-attended flight.
Put it another way: if, say, you got into your car and were advised by the police that for your drive to work you should have an armed escort, would you just accept that or think long and hard about going? I think I know what I'd do ...