Yeah I'm not against border control, I just don't think it should be used to stop people from crossing. Freedom of movement is important; for some reason we've come to believe that countries are like prisons and people should be stopped from escaping them.
Still, even if you had immigration controls... There were eight IS terrorists with explosive belts on, a few more with guns. Some of them were born in Paris. Are you really going to keep hundreds of thousands of refugees penned up in desperate conditions in order to stop about three or four terrorists from getting through?
The logic on that idea is comparable to this: Two guys from Michigan committed a terrorist act in Oklahoma. Let's prohibit everyone in Michigan from travelling to Oklahoma. Great idea, right?
Far more effective to just stop the guns from getting through. These guys were carrying Kalashnikovs, not exactly the most subtle of weapons. Someone seriously dropped the ball here.
The thing a lot of people don't seem to understand is, it's empty open territory. This kind of thing is daily, not just with terrorists. If hundreds of thousands of illegal immigrants can get across annually, what makes you think you can stop smugglers from bringing drugs, guns, anything? There's not anyone there checking the border.
Also, they used explosives. Would stopping the guns from getting through have stopped them from making home made explosives? That did most of the damage, anyways. If anything shooting first scared people off.
And do you know how many countries they'd have had to go through first? It's at least 6, 7, 8 countries, minimum. Probably more. If they traveled by boat it would be less, but even so, it's a wide empty ocean. People smuggle for a living. You won't stop criminals from getting access to these things.
It's not like criminals are going to choose to go through legal checkpoints. They decide to come in through wherever. There isn't some wall stopping people from crossing, or really anything. They can just walk across empty, unguarded forest or desert, like in virtually every country of the world.