Of course it isn't.
Examine the premise that muslims want to kill americans.
Examine its provenance.
Its Obama/Clinton who undertook regime change in Libya which left it a failed state, resulting in a massive immigration of north africans , previously prevented by kaddafie, into Europe.
Then they entered Syria and destabilized that country which is the mess we see today.
Then, Obama killed   thousands of innocent muslims using   drones and  bombings in all 7 of those   Middle east countries.
So, yes Trump has every reason to believe, as do the American people, that certain violent muslim groups want to kill americans and esp on US soil.
And that has happened numerous times.

Trump has chosen the security of American people over  temporary  bans of  refugees from those  7 states  .

Its the correct choice