@Jay235 Do you have kids or know people who do? Have you known or seen parents who let their kids get away with bad behavior, and then you see that the kid ends up acting like a brat all the time because they're never given boundaries or consequences? This is what happens when parents are afraid of having conflicts with their kids, acting like the boss, or clearly stating the acceptable limits of behavior, and enforcing consequences.
It's exactly the same when we, as hosts, are afraid to stand up for ourselves and our rules because we're terrified to get a bad review or lose Superhost status. In the long run, it doesn't really work. If less-than-respectful guests get used to hosts pussyfooting around them, it just emboldens them to act like this everywhere they go. Which doesn't help you or any of the rest of us.
$10 worth of shampoo? What was that about? He complained to Airbnb that you didn't provide shampoo? Do you say you do? How long did he stay to use $10 worth of shampoo? I buy a big bottle of shampoo for myself (not guests, they have to supply their own, altho I'll share if they forgot it) for about $5 and it lasts for months, and I have long hair. His $10 bottle of shampoo must have been the most expensive one on the salon shelf.