Oh dear! It's also happening in Korea.
Let me explain by saying firstly, that in English, we sometimes have a different word for a person depending on whether they are male or female. So, a lawyer or a doctor could be male or female. But we say actor, and actress; Lindbergh was an aviator, Amerlia Ehrhardt was an aviatrix.
Perhaps as some kind of over-reaction to eliminating sexism, some peoople no longer use the female form of these words, so that in America, Meryl Streep may be called a great "actor" by some people. Also over in the States, a group of people, boys and girls, might be referred to, as in, "Are you guys coming down to play?" Even a group of girls would be addressed, "You guys.."
Now, as well, it is common to hear in Hollywood films, people say (to a friend) : "Hey, man, how's it going?" instead of using the person's name; or to a stranger, "Hey, man, don't touch my car!"
So, in that greeting you mention, it seems you are on the receiving end of someone who has seen too many Hollywood movies!(lol)