Problems with the evidential reading
Unfortunately, the evidential reading of the inseparability thesis is probably false. Attacks on heritage are not always good evidence that attacks on people are imminent. While many genocidal acts are preceded by heritage destruction, there are countless cases of heritage destruction which did not lead to any direct harm to humans.
In addition, even if attacks on heritage were always good evidence that attacks on humans were inevitable, that would not dictate how we should respond in situations where both heritage and humans are under threat. Presumably our primary motivation would be to protect the people who were in danger. Yet, should we also intervene to protect the cultural heritage as well? In such cases, questions about the balance between protecting heritage and protecting people would still arise.
Answering these questions requires us to compare the relative values and costs of pursuing each goal. This means that protecting heritage and protecting humans are not ‘inseparable’ projects in the relevant sense – the evidential reading of the thesis does not work.