Which part? The part where left-leaning activist groups generate enormous numbers of bogus voter registrations? Among others, ACORN did just that (getting busted doing it was why they re-organized and changed their name so nobody would keep bringing it up ... and you're probably hoping nobody will remember actual criminal prosecution for those actions). Or are you saying that the coordinated efforts to talk out-of-state college students into double-voting haven't, despite extensive reporting of exactly that, occurred?
Or you could look to no less a bastion of right-wing win nuttery than the Washington Post, which reported on a review showing thousands of people registered to vote in multiple states, and in one local review, caught over 150 people crossing state boundaries just in the DC area to vote more than once on the same day.
One of the county election supervisors who took time to review information in that instance found an example of where someone had been crossing state lines and voting more than once on the same day in local and national elections for over a decade. He said that in a dozen cases he'd reviewed, the purposefulness of the election fraud was plain, and the actions were class 6 felonies.
In cases where congressional seats or governorships can turn on a mere handful of votes, it's no "pile of bull" to point out that people are deliberately, systematically taking advantage of weak ID requirements and a weak registration system in order to fraudulently corrupt elections.