Mixed feelings. The ceremony might not have happened but for some guests and/or wedding party members the cost of plane tickets, clothes, days off of work, etc. have as lrwady been dpent. If they aleady committed those resources and there is food/party for somebody it serms reasonable to "spend" it on them.
I agree with this. Yes, one could cancel a baby sitter and a hotel, but most plane tickets aren't refundable and not every job allows a person to change their schedule at will. It's a lovely gesture, but I'd be a bit irritated on being out a few hundred for plane tickets, etc.
So you would be irritated with a relative for calling off his or her wedding, because it inconveniences you?
My husband and his brother, a few years ago, bought plane tickets to attend a family wedding several states away. The wedding was called off a couple months before, and yes, DH and BIL were out the money for the plane tickets. But, they didn't expect anything from the couple. They didn't expect to still have a reception meal, or anything. IMO that would be an incredibly uncomfortable event. They did still use their plane tickets to fly out, and spent the time with relatives.
My point is, if a wedding is called off, I would be surprised anyone still expects to be invited to the reception.
I think this family did an incredibly kind, generous thing. They took an expensive, disappointing situation and used it to do something good for the less fortunate.