I have been to Hawai'i many, many times. Lost count a long time ago. Probably at least 35-40 times? Most for two weeks to over a month. A couple of times for nearly 3 months. Each island is unique. The racism, unfortunately, on the islands is very real. The tourists and those who are in high tourist areas (the resorts, shopping and dining, and doing tourist things) don't really see it. The folks who make a living work hard in so many ways to make the tourists happy and give them a great experience, and part of that is hiding how some of them feel. Not all, but a significant part. The non tourist areas you see a lot of it. The "melting pot" has not melted as well as everyone pretends. A lot of the locals in the out areas are really wonderful souls...but some are so jaded and biased they are trouble and don't like others. Any others. The islands have seen so many influxes, Americans, Europeans (mostly British), South Americans, China, Japan, Philipines...the list goes on and on. The original Hawai'ians are often the nicest people and the most racist. All these folks are "clannish" in their lives and that is how their individual cultures are. Also take in to account the anger and such from social economic differences and successes, historic resentments transplanted to the islands (China and Japan as an example), and the bad influence of drugs and such which has really hurt the society and it just made it worse. The comments about the racism is very real...and a "local", such as DJG or MGW2233 would almost certainly experience this.
Keep in mind that except for tourism and the offshoot industries, (and most of those are relatively low paying jobs), most people who live in Hawai'i have a much lower standard income than most folks on the mainland. Add the drugs and crime, the ethnic gangs, and it is not always a "friendly" place. Especially in some places.
I still do very much like it there, will continue to visit, make a real effort to see the "real" Hawai'i, be nice and friendly to the locals, and probably retire there. But I know there are certain areas of the islands I would be a fool, no matter how good a neighbor I was, to live in. Sadly so.