I can't say I have ever been to a harsh meeting and my sponsor was anything but harsh. But I am aware there are a few groups and individuals who have developed their own style and don't necessarily follow the suggestions in the Big Book, or the traditions very well.
I think the worst thing that can happen to a newcomer is to be ignored. To say the least it is extremely rude. I travel a lot and get to visit a lot of groups for the first time, so I'm new to them. I have had experiences like Joe Nerv talked about.
I know I can't change a group, and would get no thanks for lecturing them on how to run their group, so I developed another tactic. I will stand around for five minutes to see if anyone is going to approach me. If they don't, I go right round the room and shake hands with every one present, then I will stand by the door and welcome any other arrivals. When I get the chance to share, I thank them for the wonderful welcome and explain how important that was to me at my first meeting, and hope they get the message.
Where I have stayed around and weeks I have been astonished that I have a knack for spotting newcomers, even though I don't know the group. I am very often the first person to welcome a newcomer to a group at which I am a visitor. I hope they pick up something from my example. And that is all I can do, try to be an example of how we are supposed to treat the newcomer.
Leaving the newcomer to find his own way can also have adverse consequences for a group. What he is taught by the kind of welcome he receives will have a long lasting effect on how he behaves in the group. But that is another story.