How is it not true? Like you said they wanted to get 'on the property ladder' not buy a home for life. They openly admitted they planned to stay two years then get a house.
How do you think they thought they'd do that?
That's pretty obvious. What did any young couple think they'd do?
They bought the apartment with the intention of trading up down the line when their circumstances permitted it. In a functioning economy where house prices rise gradually over time (or in our Celtic Tiger boom), the apartment would have appreciated in the interim but the house that they want would have appreciated even more (so in effect, they'd be worse off - they don't make a killing).
I know lots of couples who are now stuck in apartments that they only saw themselves in for a few years. None of them bought the apartments to make money - They bought the apartments with the intention of losing money! In an ideal world, they'd have bought a house in 2005/2006 but they couldn't afford one. Renting is not at all straightforward in Ireland compared to other jurisdictions. They therefore bought apartments as interim measures which they're now stuck with. Something should be done to facilitate these people, e.g. allow negative equity mortgages for those trading up, force lenders to include the rental income in the affordability calculations or make the tax position for such people more favourable.