Are you supposed to meet new people at a Meetup?

I went to the ethnic foods meetup group for dim sum at Kirin Court. The group seems very well organized and plans gatherings at interesting places.
I had a very strange experience at this group. I joined a table of 7 people (there were three empty seats)
As I sat down, I said, “Hi, my name is Madelyn. Why don’t we all go around the table and introduce ourselves.”
A man who seemed to be an organizer said in reply, “we all know each other.”
I was stunned. No sense of welcome
Finally I said, “I don’t know you so I would like to know your names>’
The leader man said, “you start” (I am not sure he ever even said his name)

People did introduce themselves.
But what a strange greeting and memory of the first thing anyone said to you at a meetup.
Isn’t the idea to meet new people?

At the end, I thanked the girl sitting next to me and told her I appreciated her warmth after the chilly greeting.
She said she heard it and was surprised, too

A friendly man on the others side of me already sent me a nice note.

My bad introductions to the group was probably a reflection of one member.

But I think the group needs “greeters for new people. Or a table that is welcoming to new people and designated as such.
He made it sound like a high school clique that wasn’t letting in new members. Isn’t the name MEETUP indicative of a chance to meet new people?