A) they were a lot looser with commas back in them days. E.g.:

A well regulated militia, being necessary to the security of a free state, the right of the people to keep and bear arms, shall not be infringed.

2) Some folks use commas not to represent grammatical concepts but to represent pauses in speech. Thus you could say, e.g., "I'd like you to meet my wife Peggy" without implying that you have more than one wife, but merely to indicate that when you say it, there is no pause between the words "wife" and "Peggy." Both styles go back to the days when commas were first used.