Mailchimp and other popular email marketing service providers only allow sending emails that you have collected through an opt-in form or with permission. This is because cold emails are known to have high bounce rates and spam complaint rates that affect deliverability and IP reputations (shared by many users).
Any email service provider that accepts cold email sending is likely to have poor email deliverability. That said, consider alternatives we have provided above that allow cold emails.
TIP! To avoid high spam complaints when sending cold emails, send personalized and relevant emails. Put yourself in the shoes of the people you are sending cold emails. Imagine receiving marketing emails from services that you did not subscribe to. Such emails have to be of much value to avoid being marked as spam.