It may resonate because we just don't know. There is definitely a perception that 'moderate' Muslims are allowing radicalisation to fester within their communities without speaking out or acting against it. We know the huge numbers of victims of FGM whose assaulters are never brought to justice. We know that people close to yesterday's attacker would have heard and known of his views and protected him.
Whether that particular kid is scared and upset isn't really relevant today. She simply stands as a symbol for the hundreds of thousands of her compatriots who turn their faces away.