The student's concerns about costumes were heard, some advice was given apparently, and that's all any academic organization or otherwise should have to contend with.

That's the end of the story.

There's no reason for the faculty to have to address it further.

Whether or not responses were 'tone deaf' it subjective, and certainly besides the point with respect to anyone being fired.

Students who bullied the staff should have been admonished (or possibly expelled), not the other way around.