Its is semantics, but also this is science and semantics are important. If we want to get really in to semantics we should say the experiments were done on humans, as the embryo, fetus, baby, toddler, pre-teen, teenager, and adult are all phases of the human life cycle and this experiment was done to produce genetically modified humans. Even CRISPR experiments refer to the organism model when experimenting, not the life cycle phase, unless it is specifically part of the experiment IE: in vitro vs In vivo

Saying the medical experiments were done on babies specifically is for the shock value, and it works, look at the reactions it gets. This should be a hotly debated topic, people should be concerned about the ethics of gene editing and how it is regulated. This experiment was not ethical in anyway and it was criminal, but using hyperbole to inflate the shock value for engagement is also not the way to communicate how unethical and criminal this is.