Many people suppose that when Jesus asks his question of Peter three times it is to balance out the three times that Peter denied him, but maybe it is more a matter of Jesus driving home his point?
My own reading is that if we really love Christ, and not just in words, we need to care for the members of his flock in all their variety --- the ewes, the lambs, and even the rams --- and in taking care of their needs, whatever they might be. We must care for those who think they are poor and those who think they are rich, for those who believe themselves strong and those who are sure they are weak. And those who are satisfied that they are serving God and those who don't care.
We must go into their loneliness, their self-condemnation, their sin, their poverty in religious matters as well as physical ones, and their ignorance of God's absolute and unfailing love and forgiveness, and we must there touch their lives and heal them, nourish them, and be the Good News that Christ calls us to proclaim.
A favorite hymn of mine says "They will know we are Christians by our love," an idea straight out of John 13:34-35. Do we in fact love any and all of God's children? In every circumstance? Of course not.
But are we trying?