If a therapist tells 10 people not to kill themselves, and convinces 5 patients to kill themselves, would you say "this therapist is doing good on the whole"?
From what I can gather, a lot of ML people are utilitarians, for better or worse. Which is why you're seeing this discussed at all, if we all agreed on the ethics it would have been a no-brainer.
And I don't think any utilitarian would be against "something with some harm but mostly good can be made to do even less harm".
But the person I initially replied to, obviously doesn't see it as "some harm VS much good" (which we could argue if it's true or not), and would say that any harm + any good is still worth considering if the harm is worth it, besides the good it could do.
That's certainly the impression you gave with your response. You didn't engage with the clear example of harmful behavior or debate what various numbers on either side of the equation would mean. Your approach was to circumvent OP's direct question to talk philosophy. That suggests you think there are some philosophical outlooks that could similarly sidestep the question of a therapist pushing people to kill themselves, which is a rather simple and unambiguous example of harm that could be reduced.
Sounds more like the plot line of a 60s sci-fi novel or old Star Trek episode. What would the prime directive say? Haha