How do we know that the LP candidate is taking votes that would otherwise have gone to Dino? My understanding is that LP candidates usually takes as many or more votes from the left, especially when they run on a drugs-and-gay-marriage platform like this one did.
The LP has been spending a lot of money advertising on Conservative stations; they target the conservative voter hoping to pick off a few.
If you will look REAL close, you see that the LP advertises to get the state out of marriage altogether. They don't ask the state to elevate Adam-and-Steve to the level of Adam-and-Eve. Rather they ask the state to not officiate concerning the concept of marriage. Given the current social structure of the USA, that is unrealistic, granted, but the LP will certainly not be adding "state recognition of gay marriage" to their demand list any time in the foreseeable eternity.