Downstream Casino Resort interview questions

Had a 2 hour interview. Was offered the position in the room. Then it all got weird... You have to go through what I think is the MOST extensive background check process. I understand that it is for the gaming commission but geez! Every place you have lived in the last 10 years, addresses and dates. Every employer for the last 10 years with exact dates. Now this may not seem like a huge deal but if you moved around a lot or worked at quite a few places it really can be. Filling out all this paperwork can take hours. I have passed multiple background checks for other jobs in the past. Once that is done you are then told they will let you know the results in a week. 3 weeks go by, and I did not hear a thing. I text and ask for my start date... no answer. Then I finally do get a phone call letting me know that the offer has been rescinded. I ask why as I have no criminal background etc. they refuse to give you an answer. I demand to know why... well they can't tell me because it is my "personal information". Yep, I know it is my personal information that is why I would like to know... VERY unprofessional and such a HUGE waste of my time...