And this is the folly in all of this. Teams names are chosen for local affiliation(Phillies, Nationals, Texans) or to command respect. It might be strength (bears, lions, Titans), hunters(eagles, falcons, jaguars, bengals), historical(patriots, 76ers), mystical(magic, wizards, mystics).
Were the Oilers offensive to oil workers? No, it paid homage to the strength and resolve needed to work in the oil fields of texas. Was the mascot derogatory because it was a caricature of those individuals?
Pirates were not meek people. Does that change because Tampa's mascot is a caricature of a pirate or because the mascot in Pittsburgh is cross-eyed parrot in a bandana?
Penguins are skilled survivalists and marine hunters in cold, harsh conditions - a fitting mascot for an ice hockey team. Is that diminished because the mascot looks more like a deranged muppet baby?
The truth is, that indian and tribal team names are chosen out of respect to native americans as warriors and hunters and to their societies. Whatever anyone feels or how the meaning of something can evolve or be twisted in the context of a certain time period, the notion that a sports team would seek to convey anything other than strength and respect with their team name is stupid and illogical.