Molly is 9 and just got her first period - a terr!fying, confusing biological moment. But because she was alone in a barn with a teenage boy, the adults don't see bl0od as biology, they see bl0od as guilt.
Her father Keith doesn't hear "she's scared," he hears "someone hurrt my daughter." The other father doesn't hear "tell us what happened," he hears "my son is being accused." So two fathers end up almost f!ghting over a completely natural event, while the only person who actually knows the truth - Molly - is taken inside and never gets to speak for herself.
This scene shows how fast adults project their own fears onto children. The kids were just sitting on hay bales looking at a bird's nest. The adults turned it into an ass@ult trial, a medical emergency, and a family divorce all in 3 minutes.
And that line from Ryder - "I physically couldn't do anything to her" - paired with his mom saying "Why can't anyone in this family just tell the truth?" tells you this isn't really about Molly at all.