It's not "disqualifying" ourselves,to seek God/Jesus's intervention or guidance when we find ourselves troubled by,surrounded by or back sliding into a sin,there is "willful sin" and there is "sin we need Jesus's help with".
You are talking about "willful sin",sin isn't cut and dry,there are sins we have power to keep from and then there are sins that we "need" Jesus to help us through and to be free of.
There is remission of sin through water baptism,but it takes away our sin long enough to "realize further" what sin is around us and what we can do to keep from sins,and "further establishing" a "mind set" because indeed through it we are buried and raised with Christ but alas we are "still in the world" our old sins "revisit" due to satan and we can "handle" some sins but some,we need Jesus's help with,especially "old sin" we once were a friend to.
Our sins get taken away through water baptism and belief in Jesus,but our "memories" remain,and so our thoughts can be sinful and lead us to backsliding,but that's why we are given the gift of the holy spirit,to "learn" not only in mental capacity,but spiritually as well,there is no shame in "leaning on Jesus" when we feel weak or tempted,we have power but we must always remember "whom" it comes from and "who" is more powerful than us.
That's one reason why we have "prayer" because we can't always "rely on ourselves" there are times where we will "feel weak" but Jesus is strong in our weakness,so we turn to him in such times.