The absence of metal music in the Just Dance games is a result of various factors, including the game's target demographic and the licensing costs of using such music.
Firstly, the target audience of the Just Dance games is predominantly younger people, including children and teenagers. These age groups generally have different music preferences than adults, with pop, hip-hop, and electronic dance music being the most popular genres. As such, the developers of the game may have decided to focus on these genres to cater to their target audience.
Furthermore, licensing costs can also play a significant role in the selection of music for the game. Licensing fees for popular songs can be extremely high, especially for well-known artists in the metal genre. Metal music is also a niche genre compared to more mainstream genres like pop and hip-hop. The limited popularity of metal music may make it less financially viable for the developers to include in the game.
It is also worth noting that the choreography for metal music is generally more complex than for other genres, with more intricate headbanging and moshing movements. These types of moves may not translate well to the gameplay mechanics of the Just Dance games, which involve tracking the player's movements using a motion sensor.
In conclusion, the absence of metal music in the Just Dance games can be attributed to a combination of factors, including the game's target audience, licensing costs, and the complexity of choreographing metal music for the game's mechanics. While some fans of the genre may be disappointed, the developers have likely made the decision to prioritize more popular and financially viable genres for their target audience. Sources for this answer include industry reports on the popularity of music genres among different age groups and interviews with the developers of the Just Dance games.