You can tailor the content of that email by clicking on your Newsletter from the Account Dashboard. On the next page click the “I Want To” button in the upper right area of the page.
Then click the link for the FeedBlitz default activation reminder page. This will take you to a page where you can change the settings. The process is the same for funnels. There is no way to avoid sending the dual opt-in email or to avoid the dual opt-in activation process.
As you edit the activation email, remember that your highest priority is to guide your potential subscriber toward activating their subscription. Keep the email as distraction free as possible.