Here's the thing...
If you vote the Dash members out and succeed for the next three nights (assuming there are only three left), it is certain that three other players will die (unless their doctor saves them, assuming they even have one anymore). That means that there could be 5 players left in three nights (forgetting for a second any mafia hits). Now if you are XD thats not particularly worrisome, because if they lose one member every night to a Dash explosion, they could still pull out a win. Snap could still win, but its pretty slim. However, if you're a townie and your win is based on you remaining alive...
Think about why vudu and decoyman would want to systematically take out Dash at this juncture.