Because it doesn't deserve the name "Wombo Combo." Wombo Combo was a term for a Smash Bros Melee combo constructed by players SS and Tang against Zhu during a tag battle. It was an elaborate and amazing 0-death combo between the two. Calling the Night stalker thing a "Wombo Combo" makes it seem like A: Two people are involved, and B: It requires an iota of skill.