I think its pretty idiotic to claim an appeal to authority in and of itself. Everyone is welcome to an opinion. However i agree that someones experiences (such as visiting the area) should be a factor in someone judging the credibility of an opinion. But that is not the same as saying a person shouldnt have an opinion.
That said I moved to Israel and lived there for over 2 years recently in part specifically so i could get to know both sides in the war first hand and have a real on-the-ground opinion. I found that to be a rewarding experience that has certainly effected my view and refined it.