Because with time, this light is also putting an end to not just itself but every other form of life around it.
Whether the positives outweigh the negatives doesn’t really matter when there’s nobody left around. Once we get to the point where the climate disaster is bad enough and irreversible (it might have happened already), it doesn’t even matter if humanity suddenly falls back into the middle ages and gets primitive enough to not do any harm anymore: certain processes won’t just suddenly stop.
Because with time, this light is also putting an end to not just itself but every other form of life around it.
Whether the positives outweigh the negatives doesn’t really matter when there’s nobody left around. Once we get to the point where the climate disaster is bad enough and irreversible (it might have happened already), it doesn’t even matter if humanity suddenly falls back into the middle ages and gets primitive enough to not do any harm anymore: certain processes won’t just suddenly stop.