The activation code, as stated in the code, is for analytics purposes only... several other (very popular) plugins utilize the same feature. I don't consider it black hat, in that it does not send any sensitive data -- simply the URL, plugin version, and version of WP being used (and I believe email address IF they chose to share it). Google Analytics and their Crawler collects the same exact information (and more). Still.. making it an opt-in is a good idea.
We use it to see who is using the plugin and on what version of WP. It helps us to see how the plugin is being used, so we can incorporate new features and make changes, especially with themes that have issues with the code and/or CSS. In the next update, I'll try to the analytics to be part of the email opt-in process when initially installing the plugin.
Right now, there is an opt-in to receive email updates if there are any important security/major updates to the plugin, so that would be a good place to put a checkbox to enable this feature or not.
Glad you like the plugin.