The risk could not legally be mitigated. Otherwise, landlords would have evicted en masse everyone who couldn't pay after some period of time. I am friends with a few people who own houses. They were happy to help as long as their tenants could provide at least some payment. It's better in the long run to keep good tenants than to evict them even if it costs money in the short term. This isn't true in general however, and several places have toxic tenants who have refused to pay and are taking advantage of the moratorium.

This is the literal definition of theft by decree. Making landlords whole should be top priority if their intention is to save the housing market. Imagine if they didn't - what would happen? Landlords would require stellar credit, several months payment up front, and regular financial checks. This all assuming they just don't pack up and sell their property (which has gone up significantly in value) thereby reducing the available places to rent.