All Aer Lingus flights arrive at Airside 1. Due to the fact pax off these flights 'mix' with those who have already cleared security for departing flights the TSA require the Airside 1 International arrivals must clear security before exiting for the monorail.
Meanwhile, Virgin and BA flights arrive at Airside 4 and pax from these flights do not 'mix' with departing pax who have already cleared security. Lucky those pax.
Meanwhile those of us who use EI from DUB to MCO must put up with the extra hassle of having to clear security on arrival.
Airside 1 is due to be remodelled, similar to Airside 4, whereby International arrivals will not have to clear security but due to the economic downturn the project has been put on hold.