Washington Post has an interesting article on why myths stick around:|
The research also highlights the disturbing reality that once an idea has been implanted in people's minds, it can be difficult to dislodge. Denials inherently require repeating the bad information, which may be one reason they can paradoxically reinforce it."There is no spoon..."
Indeed, repetition seems to be a key culprit. Things that are repeated often become more accessible in memory, and one of the brain's subconscious rules of thumb is that easily recalled things are true.