In Case You Thought That Only the Studios Were Stupidly Paranoid about Copyright

It appears that Actors' Equity, the stage actors and stagehands union, is also firing off cease and desist letters to YouTube. I simply don't understand the logic here. The removed clip referenced at the link was of Lauren Kennedy performing a song from the musical The Last Five Years. In what way, shape, or form was this video hurting the property? I'd argue that it was helping the property, by exposing more musical theater fans to this particular play. I mean, is anyone interested in musical theater going to not see The Last Five Years if they have the chance because they can instead just watch one song from the play on their computer? Or are they much, much more likely to seek out a production (or, if they are amateur directors or otherwise involved in community, regional, or school theaters, become more likely to try and do an actual production) now that this song has whetted their appetites. It's well-known that a cast album of a musical play greatly increases the play's chanced for future productions, both commercial and amateur. Wouldn't clips like these have the same effect?

Until Whenever