If we hear someone disrespect the Lord’s name, for example, if someone next to us or away from us says GD or JC, do we have the obligation to rebuke them/correct them?
Unless your spiritual director has told you otherwise, scrupulous consciences are not bound by the obligation of correction.
Let him among you who is without sin cast the first stone.
speak about what super Luigi told you with your priest, but even if you had to correct people, remember this: truthandcharity.net/5-ground-rules-for-fraternal-correction/
Attempting to correct people can be at times unreasonable. Most people who are taking the Lord’s name in vain are doing it out of cultural complacence with it, not out of malice. Interrupting someone to correct them is a humiliating thing [for them], and will likely cause you to be scorned and you will lose influence with the people around you. You, yourself, having good moral influence (because you always lead a good life) will be grounds to influence people when they notice that you always say “gosh”.
If they are profuse in their language, address them privately (“Hey, I wanted to let you know, I don’t feel comfortable when you say that.”)
If they are in a position where you have authority over them, such as, your students, your children, or children entrusted to you for some purpose, feel free to correct them.