I think the secret love is just when you love and care about someone, but neglect to tell them. But if you are openly rebuking them, you are showing them your love, provided you do it right!
Sometimes I have wished I had not heard it before because I've heard it enough times for a lifetime! lol I've had my share of open rebuking!
MST was dead wrong about Calvinists shying away from open rebuking, at least some of them. lol