Overall, I agree with what you are saying .... and the perpetrators would quickly be taken out. However, if your neighbor came to the door, chances are you would not be thinking you needed to have gun in hand to defend yourself from that person. Same thing with a clerk at Wal-Mart or a school custodian, etc. Much local damage could be done before folks realized what was afoot .... by the time a quick response was mounted, many small local massacres could take place ... if you expand this to the country, the numbers would add up. Conditions are very different than colonial India ... however, the ‘surprise’ factor and trusted people doing the attacking ... I think there is potential there for the radicals and per the article, they are thinking about this. It would have to be coordinated and that level of coordination with more ‘ordinary’ people rather than a dedicated group like the 9/11 attackers would not be easy. Think back to 9/11 ... it took the 2nd plane before people REALLY got the message that it was a terror attack ... when stuff starts happening, putting the pieces together quickly isn’t as easy as it might seem and that delay is exploitable by terrorists.
Yes - problems - many could be caused ... but in the many states where Concealed Carry laws are in effect ... any public shooting, stabbing, bombing would draw a quick reaction those packing heat... We have Good Samaritan and self defense shootings quite often in Texas... I recall one incident in a Mall parking lot near Dallas back in the 1980’s. A man was dragging his girlfriend through the parking lot with a gun to her head ... there was much commotion. A bystander saw what was happening and within seconds returned to his car - opened the trunk - pulled out his .357 and shot the perp. dead.. The whole thing lasted a minute or two at most... He was not charged with a crime. This was way before Concealed Carry and we now have thousands of people who just have to reach in their pockets - not their car trunks... So I am optimistic of a quick put down.