Royal Caribbean bans selected passport holders

Royal Caribbean have announced that they have banned passengers with certain nationalites of passports from boarding there ships.
Is this trumpness going too far or are they protected there other passengers?
Passport holders from North Korea, Sudan , Iran and Syria have all been banned from embarking.
The threat of terrorism is all around us , I am glad as a passenger that they take this seriously but is this too much?
We have not been given any further information other than the outright ban for any passengers travelling on these passports….will Celebrity and Azamara follow suit as they are all part of the ame group? We have not been advised of this yet but watching to see if any more nnoucements are made.

Will Mr Trump get the blame for this as Royal Caribbean are an American cruise line?

What are your opinions on this , is this right or wrong?

Are we taking things too far or is this peace of mind and would make your book with Royal Caribbean?