Wait a second -- to be strictly accurate, Social Security does explicitly state those two things.

WRT "growth in assets": they send out letters to all enrollees stating the amount of money that each has coming to them. and the number is higher than the amount the enrollee has paid in (to reflect the interest that "will accumulate").

WRT "paying out dividends": the system is paying out dividends, obviously. I know some of the people getting checks. Not sure what you meant by this.

I think it's a bit misleading to call Social Security a ponzi scheme -- mostly because it implies a ringleader, which I observe to be a dangerously appealing falsehood to many -- but your observations seem to be false.