Offended and frightened, the party of animals politely excuse themselves and Alice is alone again. Yet again, Carroll is making a case for adulthood. In the first half of the story there is this Caucus Race, essentially a game with no rules. What Alice recognizes and what Carroll hopes the reader sees is that without rules, no amount of play is really fun. It may get you dry and it may make you tired, but in the end it probably isn't much fun.
Games are competitions and competitions require rules and discipline.
Without the discipline of adulthood, life will start to become rather pointless, filled with empty ceremonies and meaningless accomplishments. The second half of the chapter is in many ways a reiteration of the previous chapter. Alice perhaps recognizes that games need rules so that they make sense, but she hasn't yet learned that rules are needed for all occasions. Conversation, to be meaningful, needs rules just as a game needs rules. And in order to successfully hold a conversation a person needs boundaries.