I’m genuinely asking because looking at the map, neither Hungary nor Poland are the first stop for a middle eastern refugee, and I have no idea where the statement of infiltrator from ISIS comes from because I haven’t heard of an uptick of terrorism in either country.
People are more reluctant to let immigrants from too foreign culture in, e.g. Poland let in > 1M of Ukrainian immigrants (they are from similar culture as Poland) during last few years. Those assimilate easily.
Also, people are afraid of the unknown. You force that on them, they will object -> vote for those that will block that. There is no way around that.
This happens more in places that are more religious and for example Poland is, if you let in people from different (also religious) culture you create a clash.
I think it would be easier for Czech, where there are few religious citizens.
As for terrorists. People watch TV -> see that ISIS is cutting heads -> EU wants to import people from exact same region into your country. Many people objected to that, even those less nationalist.
There is also a difference when you get immigrants of somehow similar culture vs large amount of immigrants from one that is completely different (and it being the same as ISIS, doesn't help, how one can differentiate infiltrator from legitimate refugee?).
It is all good if amount of immigrants is not large influx.
But what most Hungarians (and Poles) didn't take into account is that most of those immigrants prefer to get to western Europe, so blocking them was pointless. They would quickly go West.