are you serious?
You really cant figure it out yourself?

here....since you cant figure it out or trying to be a smart ass i'll explain..

I work for a Law firm. Now Law firms are supposed to be a professional business with professional people right. Now we have an email system to be used for business related reasons.
Surely people do send personal emails and such but, in this case they are sending an email to everyone in the company i work for. Including the chairman etc.. They take things like this very seriously. So since they are ridiculing him and finding humor in this chances are tomorrow some sort of disciplinary action will take place.

Was that easy enough?