The threat from Islamic terrorism is, of course, extremely frightening. But it is important when faced with such threats to keep our heads and try to stick to the facts. Even taking account of the recent rise in global terrorism, the fact is that the risk of being killed in a terror attack today is at an historic low:
https://www.telegraph.co.uk/news/0/many-people-killed-terrorist-attacks-uk/amp/
Obviously, this does not diminish the tragedy of those who are killed in such attacks, and in no way suggests that we shouldn't be vigilant or that the authorities shouldn't be taking action. But it is important to keep the threat in perspective and remain calm.
The proposal of arming the civilian population is worse than the problem we currently have. One only needs to see the epidemic levels of gun violence and regular massacres of children in the USA to see that. It is not at all wise to back ourselves into that kind of corner.
I understand it is viscerally satisfying to imagine ourselves bravely gunning down terrorists. But as your chances of being caught up in an attack are extremely low, and the simple human truth that nobody knows how they would actually react in such a terrible situation, the potential gains of widespread gun ownership are far smaller than the risks.