I live in Paris and was spending the night in the middle of the hot zone. I was a few hundred meters from the Bataclan but fortunately the area I was in was spared. I tried to get a Uber but they were unavailable, "State of emergency, please stay home", the app said. I took a city bike home, rode about 10kms and barely saw anyone in the streets all the way home. It was really, really weird. I'm awfully sad that people can be proud of having killed a hundred innocents. I'm not afraid, I'm just terribly sad. Please stop this pointless killing.
You are trying to rationalize with people who are irrational. They don't reconcile. It sucks. It's depressing.
Terrorism is usually a rational act. It is terrible, but it has political goals. This, for instance, may be aimed at ending the European involvement in Syria and their taking in refugees.
The data on terrorist attacks does not support this conclusion. Terrorism is rarely effective in its political goals and studies have concluded that it is not a rational or cost effective strategy.
Citation needed. The US and Israel are 2 rather successful examples of countries born out of terrorism.