It's probably wrong for landlords to be able to hold suing a previous landlord and winning against a prospective tenant. The winning part implies the tenant was correct and asserted their rights.
Of course, tenants being afraid to assert their rights is in the unethical self-interest of a landlord. A society that's attempting to be just should not want that.
That goes both ways. Tenant could lose and be in the right. At the very least if tenant won it shouldn’t be held against them as this discourages utilization of tenant protection laws.
Yes, it goes both ways; the tenant could have won by cheating and lying. There is no way to conclude anything without examining all of the facts and coming to your own conclusions.
Of course, tenants being afraid to assert their rights is in the unethical self-interest of a landlord. A society that's attempting to be just should not want that.