We do each other no favor by simply ignoring sins. I do not grow if I'm not called on the carpet for sin, neither does my fellow Christian grow if I don't seek to help them see their fault and need for change.
This is exceedingly hard. And it's better to remain silent and pray, than to come on in a harsh manner. Better to empathize and ask questions than ramrod "the truth" down the sinner's throat.
But at the same time unless the error of one's ways is not brought to light, there can be no hope of repentance unto life. I think of one sin prevalent among so many of us: the sin of the tongue. We grumble against each other, we talk about so and so, etc. I learned to hate such sins early on, since I saw firsthand the damage they did to others. Though I can fall into the same sin as I take apart those who are so sinning.
Unless we're willing to confess as well as be corrected in the Body of Christ, we really are not living out the community in Jesus that we in Jesus are. Tough love means we are willing to be held accountable, and willing to hold others accountable- before God and before each other.
Much more to say on this. Would you like to add something?