Well, not necessarily true. While I know that some are avoiding paying tax, the majority not living in Ireland have their own company in the country of their residence. Of course it makes more sense paying taxes and social contribution in the country where you are living, rather than where the aircraft happen to be registered... This is the main reason for me trying to stay away from what´s called the "three man scam" (that name is also a good reason to stay away from it)
I do agree though that we should get the same pay for the same job, but that is a different discussion.