Also they quite literally do not put their own food on the table. She gives them food in exchange for plowing the fields. The entire point about no adults being around is a nonsensical argument as well since she brought the children there herself. Like blud "ohh so I threw these 11 kids from poor families on an abandoned island where no adults are around, so now they need to make some iphones for me or starve to death. But its not child labor since they make Iphones to sustain themself" which is an exagerated and far more unethical example but its the same argument. They work to create a product (Creating crops on a field, taking care of her land), in exchange for that they then get food and a place to live.
Would it be more unethical to have these children live like they did before? Yes. Does that justify child laber when she could literally feed these kids out of her own pocket? Not really. She makes children work for her. Children who have no other choice then to work for her because everything else is most likely death or at best starvation. That she is nice to them and doesn't gain profit (aside from increasing her political reputation among demons and getting her abandoned village repopulated) does not change that
Would it be more unethical to have these children live like they did before? Yes. Does that justify child laber when she could literally feed these kids out of her own pocket? Not really. She makes children work for her. Children who have no other choice then to work for her because everything else is most likely death or at best starvation. That she is nice to them and doesn't gain profit (aside from increasing her political reputation among demons and getting her abandoned village repopulated) does not change that