Only because she expected them already to have come and gone.Why Shoutarou is surprised to see both of them at the cemetry
All four of those before the grave, and implicitly also herself, because they came at an inconvenient time, because they cannot bring their grief under greater control. This is very much like a person who is hurt calling him- or herself a fool for crying.who her sister call idiots and why ?
he wasn't expecting to see them so intimately holding hands