@Jonathan970 I'm a host, and I can see that it would be a very nice feature for guests to be able to filter for cancellation policy and I think your idea of a tiered refund system for strict is an interesting and fair one. I use moderate myself, so hosts who use strict may not agree.
As to your question about penalties for hosts, they are actually quite punitive. If a host cancels a reservation, they get fined $100, the dates they cancelled remain blocked on their calendar, so they can't rebook them to anyone else, and a notice is placed on their review page saying "The host cancelled this reservation xx days before check-in", which can make future guests reluctant to take the chance to book with them. As well, even one cancellation will cause a host to lose Superhost status and they won't be eligible again for another full year. So no, hosts definitely don't get off scot-free for cancelling guests.