I feel for you, that really sucks. I've always understood that those with medical issues that arise late, especially spring semester of first class year were allowed to graduate but not commission. If the new policy specifically disallows that, then I think that the new policy is terrible - not a good use of a 3.5 year investment of our tax dollars, not a good reflection on the Army who is supposed to "take care of our own", and certainly not a fair outcome for you, who through no fault of your own can't commission. there are plenty of places that you could put that degree to good use in service of your country, maybe directly for the Army, but the current policy, short sighted as it is, won't allow that.
all that and a dollar might get you a cup of coffee.
my humble opinion, and this is coming from a Navy guy who doesn't know the Army culture, is that you've been a member of 2020 for 7+ semesters and have earned the right to be considered part of that class - i'm sure you're classmates would agree. you paid for that ring with your sweat and blood (AND your own money) and nobody should be able to take it away. I don't know the legal argument, but I would definitely talk to a JAG and see what the real deal is under the UCMJ.
if there really is some sort of legal risk, and your Honorable Discharge is at stake, then it's not worth it. but if the only risk is that the institution that is kicking you to the curb might have a lesser opinion of you, then I know what i'd do...
i think keeping it as a treasured reminder of your time there and your buddies is totally justified , wearing it as a statement to the world (as Cap MJ says) is probably a different story.
this isn't the first time and won't be the last that someone gets screwed by the military. there is a reason that the saying is "they only deserve as much loyalty from you as they are willing to show to you" = "they" meaning the brass who make these decisions, or as you say "the holy trinity"
best of luck and god bless