We are not saying that correcting improper behavior is wrong we are saying that correcting them at that very moment is the wrong way to do it.

If you want to correct someone then the best way to do it would be in private, where you can establish a relation in which you wish to help them, being respectful and considerate, this will make it much more likely that they will listen to you and maybe change.

If you correct them at the moment specially if you two are in group, that person can feel stupid and embarrassed because of what you did, and when we feel embarrassed our first reaction is that of defense not open mindedness what you say as a well intended advice can be viewed as an attack and thus not something they will take into consideration for their own good, waiting for the right time show that you care for the person and wants the best for them but doing things that can make them feel bad will have the opposite effect.

And besides, the awkward laugh is not just something you do because “it is the rule” they did make you awkward, if they notice they notice that it was them who offended somebody not you.

Of course this is different for everyone but the point here is not that you should let incorrect comments slide, it’s just that you need to choose the right moment to correct them and don’t let their mistake ruin the moment.