The second most striking thing is that Trump's critics are reading much more into his words than is actually there. Contrary to public perception, Trump has not actually said anything about Islam as an ideology or Muslims in general, as far as I'm aware. He is clearly not an intellectual and has no real understanding of the ideological roots of Islamic violence. He approaches it instead like a practically-minded businessman. "We are letting Muslims into our country. Some of them seem perfectly pleasant and well-integrated but nonetheless engage in religious warfare against us. We have no means of readily distinguishing the Muslims who pose a threat from the ones who don't. Therefore the only sensible solution is to block any further Muslim immigration." That, in summary, is his thought process on the issue and it is both perfectly rational and perfectly moral.
How is what Trump has suggested different from what Britain did in World War Two when it blocked immigration from Germany and interned many Germans and Jews who had previously lived in Germany?
Refugees in an Age of Genocide: Global, National and Local Perspectives By Katharine Knox, Tony Kushner
This was a wartime expedient, to be reviewed once the war was over. Trump is proposing a temporary measure to be applied until the jihad problem is resolved. Perhaps there will come a time when jihad is no longer a threat, and Muslim immigration can be allowed to resume. Until then it should be stopped. We are engaged in a war much like WW2. It's time our politicians recognised that this war exists and took the appropriate measures.