This kind of myth's is not totally avoidable or new since people think negative on new things discover especially if we talk about finance and investment. But what good thing here is we have venue like bitcointalk to discuss such many topics where people can get enlightenment on how this one really works and correct what they think wrong about bitcoin like they think its a ponzi or other forms of frauds.
It will become like that until no other myth will be brought to the table since their negative speculations will be cleared in the future. Then all they will do is cause panic or some negative assumptions about it. Those people who don't believe anything about cryptocurrencies have been doing this kind of nonsense from the past until now and they don't want to stop no matter what happened.