Perhaps the concept does have that role in Marxism, but I'm not a Marxist. I don't buy "false consciousness" because it is an integral part of some rickety theoretical superstructure that I need to preserve. I think "false consciousness" is a useful concept because there is evidence that various groups that are provably disadvantaged according to certain indicators either underestimate their disadvantage or deny it entirely when asked. There is also evidence that in many of these cases the cause of this is a social system that either hides relevant information from the disadvantaged group or molds their outlook on the world so that they are motivated to deny (or ignore) the evidence. As such, it's no more an excuse to protect against conflicting evidence than, say, the claim that people in general dramatically overestimate their relative performance at everyday tasks.