Pardons carry an admission of guilt.

Not true.

The Justice Department Standards for Consideration of Clemency Petitioners expressly contemplate the possibility of “pardon on grounds of innocence or miscarriage of justice.”

If the President pardoned a man that everyone believed to be innocent of a crime, would you argue that by that man accepting that pardon he is confessing to that crime?

Even if that man profusely declares his innocence and that he is accepting this pardon as part of that?

Just because SCOTUS argued that pardons carry a confession of guilt legally doesn't mean that the law is perfect, nor does it believe that just because he is "technically" in the eyes of the legal system admitting guilt, actually admitting guilt.

There is a difference between an actual admission of guilt, and accepting a pardon.