Distance and restraint
We saw in some of the photos earlier that we tend to feel our own emotions when we the image gives us a little more space.
In stories, there are equivalents of this: pulling back and watching from a distance, and showing restraint in the description.
Emotionally effective writing often understates the situation, and we as readers fill the vacuum with our own feelings.
From that perspective, maybe this snippet pushes Harry's feelings too hard on us, and doesn't leave room for us to feel ourselves.