Landlords may be responsible in certain circumstances for tenant-on-tenant harassment, a federal appeals court held.The 7th U.S. Circuit Court of Appeals on Monday did not rule on the merits of Marsha Wetzel’s allegation that the managers of a residential community for older adults adopted a blame-the-victim attitude when she complained her fellow tenants were physically and verbally abusing her because she is a lesbian.But the court revived the lawsuit Wetzel filed under the Fair Housing Act against certain staff …