Why don’t Bollywood stars speak Hindi in public?

There are not many Bollywood actors who speak in Hindi when they are in public or media sessions. I think that they should understand that they have a huge fan following among the Hindi crowd who can barely understand a word in English. They might sound relevant to the English-speaking crowd but not to Hindi ones. I feel that they should be more comfortable speaking their native language considering that we are all Indians. Even stars like Nora Fatehi and Katrina Kaif who are from different lands try speaking Hindi. How difficult will it be for Ananya or Janhvi to give an interview in Hindi considering that they are from Mumbai, Maharashtra!