Why would any person in business reduce their income to make a undesirable tenant "fit".

If there is a worse example of rewarding an undesired behavior, I am challenged to think of it.

Dun and Bradstreet has Paydex reports that would likely show UCC filings or other undesirable things for entities.

Originally posted by @Timothy Aughinbaugh:10 to 15 cap rates all over Kansas City Is that normal or has the bubble burst in Kansas City or is there another reason the NOI is so undesirable and risky?

If you can only attract undesirable tenants, you might want to pass as that is a sign the area might be more trouble than it's worth.

Increased difficulty of managing tenants and greater delinquency rates from these undesirable tenant will push the kind hearted hobby landlords to the brink of bankruptcy.

Someone could argue that your previous tacit consent to the activity limits your right to remove the new undesirables. 

This isn't a huge problem but can be perceived by some sellers as slightly undesirable (because you might not seem local).

The end result is not to the benefit of the tenant (screening has become much tighter and fewer marginal families are finding housing), we can't terminate rule violators and otherwise undesirables - leaving the good tenants that can, to go elsewhere.  

The shootings turned out to be the last gasp of undesirable residents who were soon displaced as gentrification took place and property prices started to shoot through the roof.