So the point you are making is that what people tell their partners, wives, brothers, other relatives, friends about their working conditions in situations where they can talk in a candid way isn't a valid basis for getting an insight into the working conditions and environment of a company?
So, lets assume that is the case, why do people, such as the OP, when they are deciding whether to apply to a company or researching for a job interview with a company seek out those who are or know people who have worked for the company. Indeed, you would imagine that they draw conclusions from the information that they glean.
Indeed, if I were to extend your point to its logical conclusion, then askaboutmoney.com would not work as nobody would believe or act on the anecdotal information that they receive from those who are total strangers to them.