@Robert721 What @Mike-And-Jane0 said.
Also, I think Airbnb views everything other than taxes as “host fees”, whether it is cleaning fees, linen fees, resort fees, just-because fees, or whatever other fees hosts collect as part of their revenue. Fees that get passed-through can be viewed as expenses, which they are, actually. For instance, hosts sometimes charge larger cleaning fees to the guests than they pay to the cleaner, and vice-versa. The fees are revenue, and what is paid out of total revenue are expenses. Indeed, this is the way we are supposed to declare fees on our income taxes.
Anyway, Airbnb just looks at “The total we are paying out to hosts, minus taxes” as what they charge commissions on. That way, they don’t have to worry about what type of fees are being collected from the guests, pass-thru or otherwise.