They're just fiddling with statistics on this one. With so few people as members they can easily claim higher growth but I'd be skeptical about that too.
Why not use the mass effect drivers as traps for a while before turning them off? I'd do that, pick off the occupied systems one by one if the Reapers' numbers aren't great enough to be a threat to more than one planet at a time. With these systems in hand they could wage a guerrilla warfare that leaves basically no one safe depending on some of their technologies. #observationdeck
Why start at Earth? These guys are supposed to be a galactic threat. Why can't they be more galactic-y and threatening? The Reapers just don't seem all that scary right now if they have to focus all of their muscle on this disorganized shithive leaving everyone else to get ready for action.
There would probably have to be rigorous psychological evaluations for those that do, but yeah, as a person that said fuck yeah! to the title I believe it ought to be voluntary.