Does anyone doubt that supporters of other candidates regularily hit polls?
Yes.
The others are more traditional (or simply unpopular) politicians. They don't appeal to the people who read gun or political forums regularly. Paul does.
For an analogue - you don't see 'Fudds'/hunters come out of the woodwork the same way that EBR fans did with Zumbo - the hunter culture is larger than the EBR culture, but the demographic isn't as techno-savvy (or nerdy if you prefer). (nb: there's certainly hunter-EBR crossover, but I'm talking about people who specifically identify with one culture or the other)