It's a really strange concept, before I read this thread I would have thought that someone organising a wedding event like that would at least understand that it's possible the people you want to come, might not be able to afford it. I'd assume that someone who's just bought a house and had kids would be SKINT anyway.On one hand, if I were the groom, if I were to have a destination wedding, and if people can't afford to come due to their various circumstances such as finance or lack of time to travel that far.
However, as the guest, in a million years I wouldn't expect the couple to fund your travel and costs. I think that's where the friction comes from. It would set a terrible precedent.
It's so bizarre that they got upset about it, I can only assume that they couldn't have been a truly good friend.