Trump views the current situation as a war against a conquest ideology that has infiltrated and perverted a religion. The intelligence chiefs, military generals, under Obama, have all warned that ISIS has stated they intend to embed themselves in the refugee stream. Has already happened in European attacks. He said he was going to do this 13 months ago until we had more extreme vetting. Establishing a safe zone to do this. Can Putin and Trump work on this safe zone during their phone call tomorrow? We shall see.
If you have the view that ISIS is already at war with us, this is a common sense temporary move to protect our own citizenry.
If you view terrorism as a more nuanced problem, an unfortunate form of collateral damage from free global movement, then this might be disgraceful
The comparison with Europe is not valid, as the systems are entirely different.
For a Syrian or Iraqi ISIS member to come to the States as a refugee would mean they'd have to come to either Kurdistan (Iraq), Lebanon, Jordan or Turkey and get registered as such a refugee by UNHCR. Then they'd have to apply for resettlement. Then they'd have to be lucky enough to even be considered for resettlement to the US. Next would be language and cultural trainings accompanied with thorough background checks and other forms of vetting. They'd have to fool a shitload of people of no fewer than a dozen agencies for two years to win the lottery ticket.
According to defectors which have been found to be trustworthy, al-Adnani, second in line of ISIS and one of the key ideologists who before his death was responsible for all "foreign" activities (i.e. outside ISIS territories) even stated there was no need in trying to recruit and somehow move people into the States. All that was needed was to recruit people living there online, get them to go get a rifle and they will be far more effective than any attempt of smuggling someone in.
Trump wouldn't even be able to state the fundamental difference between ISIS and Jabhat Fateh al-Sham (ex al Nusra Front) or why the two are even separately vying for contol in Syria. He probably even thinks ISIS, ISIL, IS and Daesh are four different groups. He would likely see a Shia Muslim and say it's an ISIS fighter. And he claims to have a cunning plan to win the fight against ISIS.
Safe zone with Putin? You must have ignored the entire conflict if you believe that Putin is interested in a genuine safe zone. And where? The only area where that is feasible is the north. Which already is fairly safe. But it's mostly controlled by the Kurdish, whom are under attack by Turkey, which in turn is best friends with Putin since they made up over the shooting down of the SU-25. A safe zone without Kurdish involvement is not realistic, but Turkey views any acknowledgement of the YPG as an affront.
Also, the residents of East Aleppo who haven't been killed or disappeared were forced to go to Idlib which is to the West of Aleppo. They also told fighters of rebel groups, but also those affiliated with Fateh-al-Sham, to go there. Where ever civilians go, the game will continue: Assad and Putin will claim there are Islamic terrorists among them, and they will bomb the places and kill indiscriminately.
Working together with Putin will not accomplish a safe future for Syrians, it will further mean working together with Assad, Hezbollah and Iran, and it will be a most devastating message to the rest of the world (which after this past week is quite difficult, but Trump never disappoints).