Secrets are one of the central themes in the book, although they are not the most prominent theme, they are quite important, as the ending of the book relies heavily on an untrue fact and untrue story, or rather a secret, which determines the fate of one of the characters. This quote (above in your question) particularly mirrors the quote " You never really know a person until you consider things from his point of view...until you climb into his skin and walk around it." Boo Radley remains a secret from the beginning of the book until the end and this quote relates to him as Scout and Jem try to figure him out, since he is so mysterious, yet another one of the secrets present in the novel.
Answer:
For the first question: Your decision might change based on what you want to say since your personal ideals/culture will collide with your decision.
The second question: Your decision changes based on the person you're talking to since you don't want your opinion to hurt/offend the other person. This results in lying or hiding your true feelings. Also, the other person's opinion will influence your decision since it brings another fresh perspective to the situation.
Explanation:
Hopefully, this helps :)
Finding a sufficient key.
Not totally sure if this is right but I think the answer is true