It all depends upon the circumstances. In 99.9% of the cases, it is ALWAYS good, even morally correct to be honest, even forthright, regarding a situation, no matter if you are ostracized. There is an adage that it is far better for person to hate you as you are than to like you for what you are not. It is always good to express one's opinions &/or beliefs even it is contrary to the masses. Most people are threatened, particularly family, because it disrupts their comfort zone & level. It also threatens the familial &/or societal construct & status quo.
However, in the corporate world, it can be highly deleterious career wise to tell the truth. Telling the truth, in some cases, can be a downright career killer for the one who is telling the truth. Many people in corporations are even blackballed unfortunately for telling, even divulging the truth especially against those who are in very powerful positions. Many promising career paths were ruined, even destroyed because one elected to tell the truth about a certain job/corporate situation. Many just simply kept their mouths closed even if they do KNOW, realizing that their careers are at severe risk. Their mantra is to put/shut up.