It would have been better for them to strengthen the leadership of governments who were ravaged with terrorists, like Nigeria or Somalia for example, instead of taking matters to their own hands and incessantly bombing those places - which is not an efficient solution (let alone a permanent one). Because the only thing bombing accomplishes is making them into a boogeyman for the victim countries.
Sometimes I feel that these developed nations make money from wars and conflict. All the countries they invaded with the aim of fighting terrorism are currently going through greater security challenges. Libya, Afghanistan, Syria, and Iraq are all suffering from the effects of the so-called war against terrorism.
Nigeria is gradually becoming a terrorist hub where they carry out their terrorist activities without any stiff opposition. Yet funds that have been marked to buy weapons a siphoned by corrupt government officials and kept in European and American banks or used to buy choice properties. Thereby giving these terrorists the impetus to keep on carrying out their criminal activities. Instead of waiting till they become a threat to the world, these developed nations should assist these nations to counter terrorism and help curb corruption and money laundering.
Notwithstanding, we remember these innocent citizens that lost their lives in the 9/11 terrorist attack and we also acknowledge the sacrifices of many selfless servicemen that died in the cause of saving lives. We remember all those that have also died as a direct or indirect result of terrorist activities around the world.