If it wasn't racist why should he apologise?
The chap is just concerned about his safety, especially when laws are flaunted for people of certain religions... certain religions which come from certain countries where higher than average numbers of people aren't developed enough to act in an empathetic, civilised manner.
Maybe i'll wear a balaclava next time and see how far i get, the recognised attire of the IRA. If i get asked to take it off i'll accuse them of stereotyping.
Usually you have to apologise for being rude, which he really was. He could have done the sensible thing and just said nothing and gotten on with his life, instead of taking the miserable old fart option of saying something smart and then being held to account for his rude, nonsense views.
Please don't think you are taking action by wondering through airport security with a balaclava on, you are just going to look a fool trying to make a comparable situation out of it.