Because the non-Catholic does not believe in the Sacrament of Reconciliation, he can’t validly receive absolution.
1 John 2:1-2 NASB
My little children, I am writing these things to you so that you may not sin. And if anyone sins, we have an Advocate with the Father, Jesus Christ the righteous; and He Himself is the propitiation for our sins; and not for ours only, but also for those of the whole world.