It's also because the "beta" trolls interact with the beta kids, and the "alpha" trolls (to a lesser extent) interact with the alpha kids.

The Alpha trolls actually interacted more with the Beta trolls and kids than they did with the alpha kids. In fact, Aside from Aranea talking to Jake that once, Meenah trying to kill dream Roxy, and Aranea highjacking their session in the GAME OVER Timeline, they really didn’t interact with the Alpha kids.