Why is George's mother such a big character?

Why is Estelle Costanza (if I remember the name right) such a major character in this movie?

I mean, I have given up hope on this movie a long time ago, but she's a really annoying actor - of course perfect fit to be George's mother, not such a great fit in this movie.

People would scream their heads off if an old man was flirting with and trying to seduce a young woman the way George's mom talks with and about Charlie's character. How is that not demeaning and sexist? How is that not misandristic?

What does she even do in that newspaper? Why doesn't she have a computer, either? Because then we'd see some computer cords and cables?