If I understand the story correctly, and if its not a hoax or something the person who wrote the note was bold enough to go inside their hotel room while they were away from it...racial slur or not I can certainly relate to wanting to call the police if somebody other than house cleaning was there.
Yes, it MIGHT be worth it for “entry”, but then, it’s a hotel. I’d insist first with the hotel that they see if it’s their staff (most likely). Is it hard to get to CCTV to check on the hallway? Never mind logs of staff working there. Because technically staff ARE allowed access.
Still, it’s as if they were all upset only because of the word. Dollars to donuts if it was just a strange card left on their dresser they wouldn’t even call the desk, much less police.
If this really is how it went down, what would give them the idea it was someone other than housekeeping?