Considering these often quoted scriptures, "He who is without sin, cast the first stone" & "judge not lest you be judged," are we never to find fault? Well, let’s ask this. Is it wrong to point out sin? No! Jesus was often doing so; with his disciples, with the people, with the religious leaders. Pointing out a person's sin can be a loving thing if your goal is freeing them from it. If your desire is to justify ones self or to condemn someone else then you are in the wrong, because you are not acting in love.
Can covering a sin be love? Yes and no. Covering to protect a person from ultimate condemnation? Yes. Covering to protect your self-interest? No. In the first case, your purpose would be as a part of a restorative process. In the second, it would either thwart or delay a repentance or sanctifying process, leaving the person in the dangerous position of being judged by God. "...he who turns a sinner from the error of his way will save his soul from death, and will cover a multitude of sins." "If you see your brother overtaken in a fault, you, who are spiritual, restore such a one in a spirit of meekness."
Love has one simple goal; whatever is best for the loved one, in the long-run.