I recently received an email from someone because because it was too difficult to sign up for my newsletter. Mailchimp uses double-opt in and the steps ended up

I recently received an email from someone because because it was too difficult to sign up for my newsletter. Mailchimp uses double-opt in and the steps ended up being 1) fill out email 2) confirm email address 3) click 'I am not a robot' button. My newsletter open rates are around ~45% and click rates are ~15% which both seem to be pretty good and I attribute this to the fact that you have to really want to subscribe in order to do so. Given that I pay based on the number of subscribers I have, and that the purpose of my emails is to point people to the website, I actually periodically unsubscribe people that never click/open them.