You have a few options:
Rather than refusing to sign your counseling statement, you can sign and write a rebuttal instead.
Option 1: You could refuse to sign. This does not usually help the situation and can ultimately put you at a significant disadvantage. If you happen to be working for an unethical leader, you empower them by not signing. The leader can simply write “Soldier refused to sign” and sign/date the form himself. At any later date the leader could write a counseling statement without your knowledge, and simply write “Soldier refused to sign.” You’ve set a precedent at that point. If you try to contest the counseling, the leader can say, “He always refuses to sign his counseling statements.” It then becomes your responsibility to prove the counselings did or did not take place. You are now on the defensive. The odds of this happening are slim but why put yourself in this position?
Option 2 (Recommended): Disagree with the counseling and write a rebuttal. If you need time to write your rebuttal you can request a reasonable period of time to respond to the counseling statement. Write “I request 24 hours to properly prepare my response to this counseling”.