So let's say somebody steps into your office, opens your network closet and leaves a laptop there overnight. You don't know who it is and you see it sucking down some data from some service you incidentally pay for.
Can you honestly tell me that when you discover the laptop doesn't belong to anybody in your office, you'll just step out the closet and let it continue doing it's thing while you wait for the owner to return?
It's clear nobody cares about JSTOR, what Byrne is bringing up vis-a-vis historical precedents of civil disobedience and closes with is that when you find the laptop, your real worry isn't about JSTOR's feelings, it's the subterfuge.
Why it's 'complicated' and 'sloppy' is because you now have to divorce your feelings about your network's violation from your ambivalence to casual TOS violation, which is hard.