For white people who say these things, they believe that they are being infringed upon by a group of people who don't look like them or have the same tastes as them. The extreme would be that they don't like them. This is not to say that all the patrons of bars and pubs are like this but you get the feeling that many, if not the majority, feel this way.
What does it mean when another person from another race comes into an establishment that is made up of white people? It means that they want something to drink. It would also be true to say that many people other than white would like to find someplace that caters to their cultural identity when it comes to food and spirits. In Maine, that is not possible unless that person was to start their own business but many people are not interested in going that far.
Another place where race is played out is the dance club. The owners need to attract people to come in and dance (actually, they want people to come in and buy alcohol, and dance). The owners, most of them white, use what is considered "cool" and "hip" to get the young people through the doors. If you were to go into a dance club, you notice that the music that is playing is mostly hip-hop, a "black" genre of music. Many of them play techno, a "white" genre of music also. When one genre of music is being played, the other group complains. "Why are you playing that music? We didn't come to listen to that!"
Again, everyone thinks that this is their space, when it is the owners space and they want to make a profit. For them, they have to use what they think is commercially viable. In the minds of most white people, what is considered "black" is considered "cool" and they have no qualms about using the images and music to make a buck.
Night life is just not about music and drink. It also comes into play when we meet each other. Take the way racialized people greet and introduce each other. White people ask what you do for a job. When black and hispanic people introduce themselves, they are not concerned with what job you do. For blacks and hispanics meeting white people, this can be frustrating because they are more concerned with meeting you. There profession or job is not a status symbol as it is for most white people. This is not to say that the way white people communiticate is wrong. It's not. I would say to white people that you don't have to be preoccupied with what you do for a living and just have a nice time meeting people.
How we entertain ourselves is racialized but most of the time we don't know it. Unless a person is trying to enter a private club, people should let people who don't look like them in and enjoy their company. That person, regardless of their race, wants to be there.