But how can you check that their encrypted vote is not tampered with even if it's well formed? I can craft "virtual individuals" which replace the real people voting and you wouldn't even notice. The vote is cast and well-formed, it's just not their vote.
If vote is secret you just know that someone voted X. Who is that someone? Is he even real?
Since we need secrecy we need to know X, but not who is "someone", so we're blind there.
Every encrypted vote is linked to a voter registration. As with the current system, you can determine if someone has voted but not who they voted for.
If you can't prevent fake voters from registering, you've failed before the election even begins.
(Yes, this does allow you to coerce people with known preferences into not voting in order to affect the result. This issue, and many others, are discussed in the video.)
All the 'did I vote for the person I tried to vote for?' happens either in the voting booth, or by choosing unused ballots to audit at random.