You know, it is so close to getting it. Yes, it is possible to kill a child without violating the law. But people will still get upset! Why? It is almost as if just because a thing is legal, that does not mean that it is morally acceptable or that it will not lead to some consequences.
This is the same attitude that is happening in the US Supreme Court. Alito and Thomas in particular are constantly furious that they are being criticized even though their bribe-taking, constitution-shredding, and insurrection-supporting behaviors are not technically illegal.
There is a large cohort of people who believe Lawful = Good, that they are inseparable from eachother. D&D got that dynamic right, they're definitely two different axis.
What is the context here? There are lots of things that are “legal” that shouldn’t be. There are entire systems that are oppressive, corrupt, and designed to commit crimes against humanity. Pointing out the fact isn’t necessarily an endorsement of its existence, nor is it saying it’s ethical.