do you think this would attract that type of tenant who is possibly selling drugs or doing other illegal things?

Some recommend you start a C or S Corp to avoid dealer/trader status with the IRS, especially if you plan on wholesaling some of your properties you get that you do not plan on flipping.

While I won't defend him on run down rentals I think it is unfortunate that society wants to hold him responsible for vacant properties and drug trade which he did not create.

The Commission take steps to clarify the cunent ambiguity in broker-dealer regulation by determining that persons that receive transaction-based compensation solely for providing names of or introductions to prospective investors are not subject to registration as a broker under the Securities Exchange Act. 2.

It is the reason my Mom and Dad got divorced when I was 3 yrs old was because of his drug and alcohol issues.

Is it illegal to ask potential tenants if they can pass a drug test? 

When a car dealer buys a car from the manufacturer and resells for 50% more, how is this different? 

It is simply asking for a free pass to be a dealer provided you own the real property.  

Seeing that it was a dealership, I am assuming a car dealer here, but regardless you may have an environmental issue on your hands. 

I happened to have the criteria of no previous evictions as well as no smoking and no drugs.