BuddyPress.org

Sure you can change that link as well as content of confirmation email by adding the following code in you function.php;

add_filter( 'bp_core_signup_send_validation_email_message', 'custom_buddypress_activation_message', 10, 3 );
 

function custom_buddypress_activation_message( $message, $user_id, $activate_url ) {
    $user = get_userdata( $user_id );
    $activate_url = 'http://www.domain.de'; // change this link to what ever you want.
    return "Hi $user->user_login,
Thanks for registering! To complete the activation of your account please click the following link:
$activate_url 
Thanks,
Jesin";
}

For more details you can visit the following link;
http://jesin.tk/custom-buddypress-activation-email/