Any landlord operating in an environment where Fair Housing laws apply should acclimate to the fact that whatever they feel in their gut should count for nothing and (unless they want to be on the wrong end of a discrimination lawsuit) should  have demonstrably zero influence on how rigorously an application is vetted. 

You can have higher standards, you also have market influences to deal with and your standards must be consistent and fair.There are really good Sec 8 and PHA tenants, not all are down and out trouble makers, that is where your experience and knowledge come into play, nothing says you must accept a Sec 8 tenant, it says they get the same chance to lease as everyone else....and that is if your property meets requirements too.

I'm getting the feeling there is some emotional or other non-rational influence going on here. 

I know it's not down on the Plaza, that's A in KC.Are you familiar with the tenant's business, type, industry ROI, market, what influence their income to pay higher rents, their ability to pay?

I've been added on a list that deals with the GMA so they do exist.Lastly, I would also suggest, if not done already, that anyone looking to invest on the island gets familiar with the different neighborhoods as that could influence your purchase.  

People who don’t respect your time and who try exert negative influence are the ones you can do without.

It will, however, be counted within your adjusted gross income - which may influence your ability to qualify for other deductions, adjustments, or tax credits.There are a lot of moving parts and variables here.

I would have your father talk to his own CPA and not to influence his decision. 

Some people find their niche and strategy quickly while other people find it overtime as the market and other influences define them.

Here are some great books that I have read and have provided some great insight not only in Real Estate, but also in life.Millionaire Real Estate Investor - Gary KellerRich Dad Poor Dad - Robert KiyosakiReal Estate Advantages – Sharon Lechter and Garrett SuttonThe ABCs of Real Estate Investing – Ken McElroyThink and Grow Rich – Napoleon HillThe Seven Habits of Highly Effective People – Stephen CoveyHow to Win Friends and Influence People – Dale CarnegieE-Myth by Michael E.