What about Afgan/Pakistani refugees?
It’s a political decision, which, in relation to Iran, Syria and Iraq (some visa holders and immigrants) was already implemented during last 2 years of Obama admin. Not new.
However, the US had had a large intake of Syrian and Iraqi refugees in recent years (Bush and Obama admins), because the countries were invaded and war-torn. To a lesser extent same for Afghanistan.
Iran, OTOH, has insignificant numbers of “refugees” exiting Iran and applying to enter US. Anyway, many are Afghan refugees currently residing in Iran. So, it really doesn’t matter.
Also, I find it funny Lebanon is not included on the list, since Hezbollah are in fact Lebanese and have many Christian members.
It’s a political decision, not a terrorism related one.