Let’s take a moment to look at Star Trek’s holodeck.
We know that it is capable of creating realistic facsimiles of an environment through the use of force-fields and matter conversion systems, such as are used in the replicator units.
A replicator can make any one of a number of foodstuffs, materialising it from raw matter. This matter must come from somewhere. On a closed system such as a starship, we can posit that it is stored somewhere on the ship, waiting to be dematerialised, then rematerialised in a replicator or on a holodeck.
So a holodeck can recreate practically any scenario. What do you think the crew of a starship are going to be using these 24th century facilities for?
That’s right. The driver of technological advances throughout time.
And not just rude pictures either. The holodeck can use its force-fields and matter conversion systems to allow all sorts of simulated naughtiness to occur. And there’d be no need for prophylactics, because a holopartner could never become pregnant, or infect you with an STD.
So we can also assume that various bits of waste are left in the holodeck after a session. How do you suppose we clean the holodecks?
Well, given that the holodecks use transporter technology, and that we are on a closed system such as a starship, I think that we can safely say that it’s dematerialised for later use as raw matter in a replicator system.
We are all of us, in a very real sense, eating Commander Riker’s jizz.