States don't mail people unsolicited guns. You don't need to go through a background check before getting a ballot. If you request a mail-in ballot, it doesn't go to a third party to run a background check. There are no mandatory wait periods on ballots. Here's a good source:

David Hogg gives a biased opinion on purchasing a gun vs. enrolling to vote. Although some voting qualifications have made it more difficult to register to vote, it is still more intensive to register a gun. As a public figure this tweet can be taken as fact by some.

It is completely false that it is easier to buy a gun than it is to vote. anyone that has bought a gun, done the background check, filled out the paperwork, etc knows this. It's a lie to say otherwise.