don't bother explaining it, let anyone who thinks bitcoin is scam, pyramid, ponzi,... continue thinking that way. i want less people buying bitcoin now that i am buying so that i can buy more as long as bitcoin is still cheap. if they start changing their minds now, price would rise and i can buy less amount with my fiat.
and these people will understand how they fell for a stupid FUD when they start seeing "bitcoin is accepted here" signs everywhere. if they happen to go to Japan now, they can see them already in a lot of shops.
I think people who don't what is bitcoin are might be mislead with wrong information. This can impact on genuine users too. As they will also think that Bitcoin is scam, pyramid or ponzi scheme.
Rather we can explain them as Bitcoin is future. Technology behind Bitcoin is real invention.
Many of think or even ask me too that who is main authority behind. I would like to clear it as There is tremendous energy (electric) is used to make proof of work by running servers and nodes. Which get rewards for solving such encrypted data and storing it on open ledger. And generated rewards are Bitcoins. Bitcoin have strong power behind it for backing.