Can you please post a link to where the claim that many non-citizens voted is debunked? I would find something that proved that to be worth a read.
The people in this video were likely brought on because they were foolish. They were brought on to make specific claims that they wouldn't be able to do a great job of backing up so that the CNN host could be dumbfounded while also not being in a position to have to provide any real evidence of her own.
Well, for starters there is no evidence that proves millions of people voted illegally. Last Saturday there was a recount in Wisconsin, and nothing was amiss.