This is true. However, they were completely unprepared for it back in Feb/Mar, had completely undetected infections coming onto the islands, and weathered the storm quite well. This time around they know a lot more about their enemy and the challenge it presents, they have tools available they didn't have before (like testing!), and they know what works for minimizing spread (masks, social distancing, washing hands, sanitizer, etc.). It seems to me that even if they were to open the flood gates June 1 and allow ANYONE in (not advocating that, just making a point), just as they were doing on March 15 (they didn't start shutting down business until about March 18), they would have less problems than they had in March and April if only because everyone knows more now. (I believe they initiated the 14-day quarantine on about March 22.)
So, now, if you add pre-flight testing so that the positives are removed from the flood of tourists coming in, you will have MUCH less infection arriving than you had arriving on March 15. Combined with the fact that there is no doubt the number coming will be dramatically reduced just due to fear (estimates are it will be several years before Hawaii has all of its tourists coming back), plus all the knowledge we all have today (asymptomatic spread, testing, benefits of masks and a 6' distance), the results would be way better than it was in March/April, and Hawaii was probably the best in the Country even back then.
All of that leads me to believe Hawaii is not giving itself enough credit, and is understating it's ability to handle the result of tourists/tourism. In hindsight, it appears they were quite well prepared for what came in the first wave before they even knew it was coming, and so this next wave cannot be as bad or as problematic and they are surely prepared for it.