This case is similar to what happened when I was a teen. A convenience store limited the number of teens in the store at one time. The teens argued he was discriminating. He argued it was his property and he was protecting it.
The one thing I remember is that teens would still go to the store. Even the ones making the most noise.
There is a bit of a difference in that the store reserves the right to refuse business with anyone, and so he was probably within his rights to limit the number of people. You can pretty much put whatever conditions of entry to your property that you want, but you can’t bar people from exiting.