I thought on it more, because yeah, that wasn't a very good reply, I just tossed it out and had to come back and think about it again.
Tell me if this jibes any better: If you're expected to produce a paper on a subject, for instance, and you think that you're never going to be called on to prove that you understood what was in that specific paper, then it's a simple matter of deciding whether you're willing to cheat or not. You aren't involving yourself with the work beyond obtaining it and handing it over; it's just an object to you, you never see or think about the contents.
How often does plagiarized work have to be read aloud, or otherwise followed up on? If the answer is "quite often" then my next question is: do they know that, or is it usually a surprise when they get called on it? Or a gamble that they're hoping to win? Because if you think you'll never get put on the spot, then you can make the decision to cheat believing that you'll be done thinking about the work you stole the moment it leaves your hands. An understandable, if unfortunate decision that a perfectly normal person could come to if they're under pressure or just have an ego that exceeds their sense of ethics.
Compare this to the act of preparing a script which you intend to read, in your own voice, and then continue to be associated with indefinitely, in front of an audience of (you hope) millions, without apparently understanding anything that's in it, and then choosing to do that every week indefinitely as your primary source of income. I don't think that's a situation that just anyone could end up in, simply because of the immense toll it would take on the soul - and that's coming from someone whose cynicism registers on the richter scale.