Remember, always (this coming from a former corporate Exec), the HR department doesn't exist to protect you, but for the safety of the company. It is awesome you stepped up, and you should, but do not dwell on this event whatsoever, or they may find that you may be a potential problem and find a way to release you sometime in the future. Do not dwell on this event, it is reported and officially scrutinized, obviously if it happens again there must be action.
But do not dwell on it just because some azzbag did a hateful thing. At these times we must be strong.