Reading the OP carefully, it is clear there are a lot of implications that can be derived from choosing to limit service outside of what the law requires.
As a thought experiment: Suppose Oracle and Google show up and want the service. Oracle is known to be an aggressive company with respect to business and so the company denies Oracle... but accepts Google since Google is friendlier.
Does Oracle have grounds for suing ? I don't know. IANAL. But if I was in their position, I would be concerned until I consulted a lawyer.
What about other entities: political parties you disagree with? activist groups you disagree with? businesses who have unsavoury practices?
Put anther way, what can you legally say 'no' to, and what will get you sued for denying them?
If you can provide a straightfoward notice "no patent trolls" (enforceable in court), does that insulate you?
Again, I don't know. But it would give me pause to ponder if (when?) I am in the position of providing services.
--- more thoughts---
If you take the onus of determining who is moral onto your shoulders, you take responsibility for the inevitable screwup. And with that, you ensure that you will be arbitrary when you notice that one entity is an exception to your existing rules. You have to modify the rules, and that angers people (notice Blizzard's forums anytime changes come
Where the line? Where the exceptions? How to handle it? out!) This is a scaling problem.
Can you get away with not overthinking it and simply kicking the odiousness to the curb and hope that the scaling problem won't manifest?