I'm sorry if you didn't understand my response, but what I wrote is in face relevent.
Here is the crux of your issue: as a USC, you are eligible to receive benefits without repaying them (unlike LPRs), BUT: as a petitioner and sponsor of an immigrant, receiving benefits COULD make the consular officer feel that you are not in a financial position to support an immigrant. In other words, they may think that if you have to rely on public benefits, the immigrant might try to do this also, which is not permitted.
This is why I brought up making a plan to provide insurance for your beneficiary. It is all connected and part of the totality of circumstances that inform the public charge evaluation made at the interview.
YMMV.