Brilliant, well-told, sad.
Bullying and the ostracization of the Other unfortunately happen all the time. This manga, through the perspective of the bully, offers insights into the type of mindset that can lead to such behavior--the annoyances and pettiness--and also shows an excellent example of scapegoating. My heart ached for Nishimiya and, to a lesser degree, for Ishida as well.
It appears that this one shot leads into the main series, which I assume will pick up five years later where the final scene left off. The ending makes me want to read more about how their relationship will develop, though it does also resolve this one shot pretty well.