Without considering the moneyside, but pure reality of a currently 100 person company hiring by minimum thousands of moderators. Let alone trying to make sure every global chat would be moderated 24/7. Not forgetting to watch the watchers so that moderators do not abuse their powers.
Last but not least, who in their mind would want to be a global chat moderator? Imagine the fun of reading global for few hours in a row looking for infractions?

