Yup. Exactly. But apparently logic is not @snowram's thing.
If people can CHOOSE to play with a smaller party than intended, why not also be able to choose to play with a larger party than intended? It is EXACTLY the same thing. Anyone who cannot understand and appreciate this very simple point is clearly incapable of following basic logic.
You seem to be on the left side of the Dunning Kruger curve. You don't want to understand why increasing the default maximum value would naturally make everyone pick a 6 man party, in a game balanced for 4 players.