Rejoicing in moral wickedness is at variance with biblical love and does not have humanity's welfare at heart. Divine love cannot be divorced from objective truth. Love bears all things. Love supports, uplifts those who are in need of such. Moreover, one who operates out of love will cover, i.e., be slow to expose, the mistakes of another.
Love believes all things.
This does not mean that love is gullible. Rather, the apostle has something else in mind. Love will give the benefit of the doubt. In these times when error is so rampant in the church, we must resist the temptation to be quickly and recklessly suspicious. We should strive to be more trusting of our kinsmen in Christ.