(My last post on this topic., Ill let you all have the last word on my posts) 1 semester? For me, I am not a Lawyer, but I did sleep in a Holiday inn.
I am sure in the semester you were taught that all U.S citizens, individual or corporate can seek redress in U.S courts for equtable relief where as you state "clear case laws, etc exist/existed along with a legal infrastructure for complaints, investigations, trials, and punishment/award of damages." This is the base premise of my argument.
Paypal is not the FINAL ARITRATOR, the courts are! I ll address it later in post.
Regarding Scenarios #1-#5. ALL companies/organizations/individuals require
prior approval from Paypal in order to send and receive Paypal payments. As a
private company, Paypal reserves the right to refuse service from any entity or cancel any entity from using their pay platform for violations of their user agreement or at their sole discretion at any time for that matter. That has always been their right! Your scenarios #1-#4 assume that these organizations would have been given prior approval even if upfront they violate Paypals user agreement, or company values. Highly unlikely scenarios. For sake of discussion, If they were prior approved and later found to be in violation of PayPal user agreements or company values, we can expect them to be expeditiously canceled by Paypal.
Your scenario #5 has merit regarding the fine. As I stated before, what is objectionable is the $2,500 fine only because the user agreement outlining violations is poorly written, can be perceived to be ambiguous, and stretched to be construed to extend beyond the scope of a standard user agreement and violate 1A. However, I am sure you learned in your semester that ambiguous contracts (especially if fine is levied arbitrarily after prior approval and without adequate notice) are voidable, and that contracts that violate state and federal (Constitution) law are unenforceable.
The way I see it, the vast majority of Paypal Users trust and appreciate that Paypal is acting in good faith to rid their platform of undestirable elements that do not adhire to the user agreement or reflect their corporate values. And if by the improbable chance Paypal is trying to abuse their user contract and arbitrarily fine their users, it would not hold up in court and as we know, (as well as Paypal) Paypal would no longer exist as a viable entity.
PROTIP: If your legal argument points of authority example Child *********, KKK, or parties circumventing U.S sanctions, you may want to rethink your legal strategy!
Solution: Dont keep any funds in a Paypal account. That is a a bad practice regardless.
Peace. 
