Because we have grown is no indication of how much could have grown (or shrunk).
Again, I am looking at this in the context of winning elections. I know people don't like the idea of shirking away from some subjects - it has a slimy feel to it - I know that...
I mean... if we had the national spotlight on us leading up to an election, I would rather a sound argument against the Federal Reserve be highlighted than how "aliens are influencing the elections" (which i made up - so as to not single out any particular theory).
I can also imagine an article listing out some of the topics that where highly popular here being used against a future candidate (particularly Rand Paul since the site carries his surname)... And again, yes, I feel the 'screw the msm!' sentiment... but it would be politically wise to forestall such attacks.
So, it is in this light that I think 'conspiracy theories' are bad for the movement.