Whats the reason that many women in person are fine with it when I say I am trying to say Hi to new people but on Instagram they ignore it?

So yeah this is one of my biggest question. In person when I approach women whether Indian or expat in a Cafe of Central areas of our city Bangalore in India like Church Street or Indiranagar or Lavelle Road, they are usually often fine with it when I say them "I am just saying Hi to new people". Like they smile and say Hi back. Even if I explain I am just trying to meet new people, they are fine with it and talks to me properly and even asks questions but when I do the same on Instagram with women, they are silent and mostly ignores. Like I mainly message Indian peer aged(21-27 mostly) women on Instagram who are in my city Bangalore mostly MBA students or interns or working professionals and I am 25 but many ignores. I explain them that I am just trying to connect with new people because University life is over but still majority still ends up ghosting or ignoring and in very rare cases even blocking. So can you explain why the "socializing with new people" line works well in the in person conversations but often fails when texting on Instagram in the dms? Like Instagram is a modern digital way of connecting tho especially for us Gen Z and the young Millennials so idk why it fails more than in person.