I think people are forgetting the US is not the UK. Meghan can call who ever she wants as a private US citizen. She is not using her title HRH. She is using her married name Meghan, Duchess of Sussex. Diana was similarly Diana, Princess of Wales and got involved in all sorts. She too was accused of meddling in politics when she sought to do good deeds such as her work to rid places of land mines. Today, these same people hold her up as a saint.
Meghan is doing good. Most in the US, where she lives, have no problem with it. The people in the UK complaining are pathetic. They make excuses for Andrew but how dare Meghan try to help disadvantaged women.
Some will even claim ridiculously that Americans will think she is acting on behalf of Britain. Seriously?!!!