If someone invests in a ponzi/HYIP scheme, the only person to blame is the person who invested in it.

Although the person suggesting their friends is somewhat to be blame, but the complete blame still goes to the shoulders of the ones who invested. Because they are putting their money at their own free will.

Point is there are a number of such gullible people in the world who get jealous of their friends profits and want to join in without doing any sort of check or maybe they are completely new to crypto having no idea that this ecosystem is full of scammers and thieves.

The LUNA scandal reminds me of BitConnect, just in another form. Those who learn their lesson are the not the targets of these, it is the newly joined users or no-coiners who start their journey in crypto via such scams, sadly.