Prof,
What would your suggestion be then, to avoid giving training to someone who will then try to murder as many people as possible? I was down in the US in last Dec to do my ATPL and had no problems at all.
Some type of screening is not unreasonable. If it was not done and another incident occurred what then would be the rammifications? Everyone would jump up and down shouting how the government failed to act.
Once you have the background check done I don't believe you need to do it again for subsequent training. Yes, it is a pain in the arse, but I for one am prepared to be patient for the better and protection of the masses.
Now if we could convince them to ban high powered sniper rifles