I don't think I have met many people who actually believe in the terrorist threat (some, but no many). People are just apathetic (me included). We have comfy lives, it is rational behaviour to just shrug our shoulders say "yeah, whatever" and change channel.
Been a while since I scanned this thread, so just seen this week old statement.
I think it's more appropriate to say most people accept there is a small terrorist threat, but the chance of personally being a victim is small.
In engineering we commonly do FMEA (Faiure Mode and Effects Analysis). You multiply the chance of a failure happening by the likely damage caused, and modify the design if the number is high enough. The exception is when a failure however small would have disastrous consequences (major loss of life). In that case you change the design - in this case taking what might be seen as excessive action.
Get over it.