If the word actually means guest room instead of inn it makes sense.
Had to have a look. :)
I had an old pastor (Very Conservative) that thought the same way as in the article (Joseph was a responsible man, would have made arrangements with family ahead of time, etc.) My pastor pointed out that in the winter one room of the house might be set up to have animals inside. Protect the animals and help heat the home. Maybe the manger was in that room. OR - perhaps the manger was brought in to the main room, kitchen or wherever the fire was. Raised up(?) off the floor to keep it warmer. Dump some hay in it for padding. Etc.
I’ reminded of an old photo of me as a baby. In some old motel room. I’m sleeping in the second drawer that is pulled 3/4 of the way out of the dresser, padded with blankets all the way around.
But as others have posted, not sure it matters a whole bunch. The idea of humble beginnings and that it was used as a sign for the shepherds is important.
Plus, it allowed the THREE wise men to place there gifts under the manger, which we symbolize by placing our gifts under the tree. !
(Hmm. Joking about both the “three” and the wise men being there around the time of birth. BUT - I just thought of my made-up, funny(?) comment about gifts under the tree. I wonder if that MIGHT be symbolic of “gifts under the manger”?)