It's not that weird. Mailed ballots can be coerced quite trivially at home, out of the view of authorities; no technology hacks or fake ID needed. That's why some of the "fact check" figures themselves are nonsense , such as the one claiming that only 0.00006% of mail votes are fraudulent. That's based on convictions. Nobody knows the real number.

In Northern Ireland postal voting is strictly controlled and monitored and permitted only in individually-reviewed case, because we had decades of coerced fraud by balaclaved men with baseball bats.