Interesting discussion between Dawkins and Harris I was just watching, where he coincidentally suggests that some knowledge is best left unknown. It can be found at 57:50 in.
YouTube - Sam_Harris_2011_1.mp4

And yes, I agree with Xei: if the algae is better why would anyone care about missing out on a sub-par virtual experience?

If ignorance is bliss, would depriving knowledge be a moral solution?
Possibly in certain cases, depending on the nature and level of the suffering that comes along with that knowledge. However I think there are also moral issues that need to be tackled over the right to decide to withhold knowledge from someone and prevent them from making their own informed choice.

As the situation here seems rather flawed, why not borrow a better example from fiction? Imagine we're part of a Matrix-like world, where we live inside a fairly comfortable VR world, whilst the real world is pretty crappy and humanity is enslaved to a bunch of machines (as nonsensical as the reasoning is in the series). Is it moral to wake someone up and reveal the truth to them that their comfortable life is a fiction, and bring them into a harsh reality of suffering?