I'm not going to move off the sidewalk when a large group is approaching
Why don't you want to move off the sidewalk even though you know there is a large group approaching?
The number of people approaching is too large for me to move off the sidewalk.
You are allowed to be on the sidewalk. Just be careful when there are people coming so you do not bump into them.
I will keep my ground. Why should I move from the sidewalk?
You are free to also walk on the sidewalk, but just understand that it is more respectable to spread out when there is a group approaching. Walking through the group will come across in a mean way.