Posts like "bitcoin is a virtual Ponzi [period]" express just broad negative sentiment. It means so many are left to come to the game later.
I'm doing my best to explain things to these people - but you're right... we have a long way to go before mass adoption. We'll get there eventually, but it'll take a lot of education and a lot of work.
It's important for us all to remember that there's nothing to be gained from criticizing others that view Bitcoin as a Ponzi scheme or scam. Explain it to them the best you can and provide information on how they can learn more about it. If they choose to pursue it further after that, then we've done our job as a community.