This isn't a method I'm familiar with (US midwest) but I wonder if it could be seen as not so much being left out of #2, but being included in #1, when normally you'd only get #3? Perhaps the HC thought people would find it more meaningful to witness the ceremony, and then attend the party, rather than just attend the party--even though they were leaving some of those guests out of the meal in the middle. I could imagine a situation where the ceremony happens to be in a large venue, the meal in a small venue, and the party in a large venue; and in thinking it over, the HC says, hey, why don't we just invite everyone to the ceremony and the party? There's plenty of room in the ceremony hall! It will look a bit silly and wasteful with only the full-day people sitting there.
And this is why we have etiquette norms. When people try to logic their way through such things, they end up making mistakes like inviting people to a wedding ceremony without providing them proper refreshments afterward.