You can enter a price of zero. But even after I figured that out I didn't want to enter my email. The "Download for free" button is deceptive and left a bad taste. I'm not going to give my email to someone engaging in deception.
I'm sorry you feel that way. It was just easy to put that thing on Lemon Squeezy to see if there are people willing to pay for this. If you don't want to put your real email use something like this - https://temp-mail.org/. many people do, it's ok.