Here is the info for Eugene from the Historical Data Systems Civil War database.
These could be the same person. I have seen soldiers discharged for disability reenlisting later in the war. Mauston is just 60 or so miles from Columbia County so he might have traveled to enlist where bounties were highest. Pretty good sums were being paid in 1863 and service in heavy artillery was seen as a pretty safe gig. Grant, of course, changed all that in 1864. I agree that MO is usually short hand for Mustering Out. Remaining at a Military prison while the rest of the unit MOs, doesn't sound good.
Residence Columbia County WI;
Enlisted on 10/4/1861 as a Private.
On 10/4/1861 he mustered into "I" Co. WI 8th Infantry
He was discharged for disability on 10/11/1862
Residence Mauston WI;
Enlisted on 7/20/1863 as a Private.
On 7/20/1863 he mustered into "C" Co. WI 1st Heavy Artillery
He was discharged on 9/21/1865
(Absent at Mil. prison at M. O. of Battery)
I don't see how the service of a young enlisted man in a Wisconsin unit (Or two) has any bearing on the question of the legality of secession. As usual, you make an outlandish statement that has nothing to back it up. But, I guess, you are: "Just Testing Ideas."
Perhaps you are correct. Perhaps I should have tried to see some humor in MildMan's last offering because, based on my previous exchanges with him, its hard to take his postings seriously. But, in this case, I believe that its simply a gratuitous provocation masquerading as an attempt at humor.
In any event, he would do well not to engage in: "Sniping", especially on threads that are totally unrelated to the topics that he brings up.