She’s been parading her hits for the last few tours, in glad to see her shedding them and embracing other songs, and so is the crowd.
Janet knows that the crowd is a mix of her super fans, her casual fans, and just regular people. Even if the crowd isn’t particularly hype on a song they don’t know, it doesn’t mean they aren’t enjoying it and getting to know it. It’s part of the experience of going to a concert.