And the letter at Yale can't really just be boiled down to "look away". Rather, it was a call for students rather than college administrators to decide for themselves what they deemed as appropriate, and it went even further to encourage dialogue with those individuals who "offended" them. So it was a call for students to govern themselves rather than relying on college administrators, and boiling it down to "look away" doesn't do the letter justice.
I think there are situations where encouraging students to engage in a dialogue, instead of flatly banning conduct that could be considered offensive, could be a useful learning opportunity.
On the other hand, I don't think there's much to be gained by asking students, especially minority students who are already doing their best just to fit in at a historically white school, to attempt to "engage in a dialogue" with fellow students who are just being jerks (for lack of a more appropriate term I can't use on these forums).
Going out in black face on Halloween is just being a jerk. I don't think that needs to be protected. There's no dialogue there. It's just daring somebody to punch you in the face, or making somebody feel bad about the fact that they're not in a position to punch you in the face.
Point being, there's nuance here. The administration of a school, like Yale, could take a hard-line stance against flagrantly offensive costumes without suspending any student who wears something that offends somebody else. As always, the solutions to problems don't need to be all or nothing.
See, I disagree with this. Having some libertarian-leanings toward me, I always err on the side of freedom. College and university campuses are supposed to be the pinnacle of free exchange of ideas and speech, and being the supposed future leaders of tomorrow, I think it's important to have students rely on dialogue and cooperation to fix their issues, especially ones that are as questionable in nature as the "cultural appropriation" argument against Halloween.
Also, I think your perception on the matter is being skewed by the narrative of black face. I didn't see any mention of anyone utilizing "blackface" or anything like that; rather, I think they were more talking about dressing up like Native Americans, Eskimos, etc. I could see where blackface is offensive, but I truly think the arguments were more focused on the generalized attire of certain populations, i.e. Native Americans, Eskimos, etc.
Besides, It's Always Sunny in Philadelphia has already ruined blackface for everybody when Mac used blackface to play Murtaugh in their Lethal Weapon remakes lol