Rotten in Denmark
I’d like to propose a quadrant of responder-types, defaults for when you see someone else in sin, which likely reflect how you respond to your own sin.
There are persistent diggers, willing dealers, typical distancers, and outright deniers.

Imagine a garden, and something is rotten in Denmark. Maybe it’s a weed you can see, maybe it’s something buried that you know must be bad.
A small percentage of persons are diggers. Maybe they are more naturally inquisitive, or cynical, but they seem made to ask questions that unearth problems. They’re ready to work. They dig.
Another percentage will go into the garden, and though they don’t intend to use a shovel, they won’t run away if you do. If something ugly gets exposed, they are willing to deal with it. It’s not their favorite, but they’re not afraid.
A high percentage of people don’t want to get near the possibility that something is wrong. They will cover their eyes, they don’t want to see. They will seek out as much pleasant superficial space from problems as possible. Too much dirt messes with their Sunday clothes.
The last group denies the garden altogether, let alone the problems in it. This takes a lot of effort, because willful blindness is its own kind of hard.
A world full of always and only digging types might be too much. A world full of distancers means weeds will take over at some point. Whichever type you default to, there are times, in wisdom, for diggers to be more patient, for dealers to be more aggressive, and certainly for distancers to lean in, not away.
But, by God’s grace, we will confess and kill our sin. Mortify your sin before you are mortified by it. And then, look clearly to take the chip out of your brother’s/kid’s eye.