“As such, why is he so concerned about Pesach hotels and not any other situation? “
There are a few differences:
The other scenario I did not mention (but happens) is this:
The hotel agrees, months in advance, to a certain number of mashgichim / guest ratio, which impacts the number of meals / hours they need to work. When the bookings are done and the guest arrive, the number of guests are FAR MORE than anticipated, (and the meal output / kitchen hours) are far more than the initial number of mashgichim can properly supervise.
What to do? Turn guests away? Close the kitchen? Let the show go on?
Like I said, its not a guarantee that these things will happen, but it is definitely a roll of the dice.