Actually, Masters himself specifically says that the illegal immigrants themselves are seen by Democrats as future voters (whether he means by illegal voting, future normalization, or what is less clear, but he very clearly is not talking about their children—who, if born here, would be natural born citizens, and otherwise would be immigrants, legal or otherwise, themselves.)
Sure, I know. I still don't think this is remarkable, given the general belief amongst a not small number of republicans that the election was stolen in some way. The last president has openly said so, after all.
Ideas about people being bussed around to vote multiple times, about the dead voting, etc. seem part and parcel with this thinking.
I would think that some mechanism to identify voters would nip this problem in the bud, but there continues to be no appetite for it amongst democrats, so there's that.