On the issue of not accepting the data as to not encourage it: that also punishes the innocent people whose lives could be saved by using that data. So I would argue that, if there is any other way to discourage the creation of such data, it should be used before deleting the data. You should not punish the innocent people unless that’s the only possible way to deal with it.
As for amoral vs. immoral: An immoral person is someone who has morals but chooses to violate them, or who has warped morals. An amoral person is someone who acts without any morals.
As for the reason for the hologram: it was a separate database about exobiology, and the Doctor apparently has limits. His matrix can only hold so much data at once. So the idea was to create a new hologram that could just be focused on that one database, and only process that.
From the episode:
EMH: If I’m to have any hope of devising a treatment I’ll need to brush up on my exobiology.
PARIS: What do you mean, brush up? Don’t you have all this information in your database?
EMH: I may be a walking medical encyclopaedia, but even I don’t know everything. My matrix simply isn’t large enough.
JANEWAY: Maybe we can do better than giving you a crash course in exobiology. Maybe we can provide you with a consultant.
EMH: I’d be delighted, but how?
JANEWAY: By isolating the computer’s exobiology data files and merging them into a an interactive matrix.
PARIS: A hologram.
EMH: That may not be as simple as it sounds. It would need to be nearly as sophisticated as I am. Tactile interfaces, personality subroutines.
PARIS: Harry could do it.
JANEWAY: Search the database for the leading exobiologist. If you want to add a personality, it may as well be based on a real person. I’ll have Harry meet you in holodeck two.