For a first email MailChimp's 1% unsubscribe rate really could hurt you.
We started using them recently and our first newsletter had a 0.5% unsubscribe rate of our users who don't want our emails but had never had or seen the opportunity to opt in or out, I just hadn't thought that far ahead when this all started and I personally knew everyone using our platform and could directly tell them about stuff.
Our second email had just a 0.1% unsubscribe rate, but with a bit of bad luck we would have been banned before we could send that one.
We started using them recently and our first newsletter had a 0.5% unsubscribe rate of our users who don't want our emails but had never had or seen the opportunity to opt in or out, I just hadn't thought that far ahead when this all started and I personally knew everyone using our platform and could directly tell them about stuff.
Our second email had just a 0.1% unsubscribe rate, but with a bit of bad luck we would have been banned before we could send that one.