A couple of Euro may not sound like much but I'd imagine leisure passengers are far more price sensitive than business passengers. I agree with you pee that it is hard to imagine the imposition of such a tax been the real reason for capacity reduction and now that it has been reversed is Ryanair's promise of 1 million extra pax a year realistic.
Irish Govt makes the travel tax back on a visitor to Ireland going to the Pub and buying 3 pints of beer.