The difference is, is that none of those names or imagery (Celtics and Fighting Irish) have anything to do with discrimination or power struggles.
The use of the word "Redskins" or the imagery of the "Blackhawks" are both repressive, and used as words or images that control ideas of "otherness" or ethnocentrism.
Being informed and aware of issues isn't being overly PC. The real issues deal with people who stick their head in the sand and say "this is the way it's always been".
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