May I know why you consider it a joke? I obviously have no much clue about it all
1. sum 500 of the biggest companies by size (price * n shares).
or
2. have WSJ editors select 30 companies by any criteria they see fit, but you don't get to see the size of the companies, only the share price.
The way that the DJIA changes isn't the same as an index of, say, the n most highly capitalised equities might (Fortune 5, 10, 20, S&P 500, etc.).