There have literally been a rash of terrorist attacks in Europe perpetrated by radicalized Syrians, Somalians, and Iranians. Not to mention the knife attack from Somalian refugee (who was getting a free ride) at Ohio State.
Read through these lists and tell me there is nothing to be worried about: https://en.wikipedia.org/wiki/List_of_terrorist_incidents_in...
Yes, being a victim of a terrorist attack is as likely as getting hit by lightning but that doesn't mean you should wrap yourself in aluminum foil and go outside in a thunderstorm. You usually protect yourself and take shelter.
Its ok to protect yourself when there is a conceivable threat.
That being said, I do feel the travel ban was hastily rolled out without much coordination and caused some people to be detained that shouldn't have been but to completely disregard the principle of it as misguided or racist in some way is just disregarding the truth of the state of world.
In fact, many pundits are saying this going to create more propaganda or create more terrorists.
First, I disagree with notion that we should care about ISIS's propaganda. People don't become terrorists because a country bans them. They become terrorists when foreign power drops bombs and puts boots on the ground in a country they feel is theirs. Others become terrorists because they are forced to or naive minded people looking for some purpose in life.
If all we care about is their propaganda we will be frozen to inaction because anything you do can be spun against you.
Furthermore, the things ISIS hates the most is the cultural imperialism imposed on them. They don't like western values and don't want to adopt any western ideas since they are a threat to the foundations of their belief system. A threat they are willing to kill for. So really you are damned if you do and damned if you don't with ISIS. It's an ugly and complicated mess and comparing to Italians or Japanese is a gross oversimplification.