To uninstall, you will need to deactivate "device administrator".
Follow these steps:
1.) on you android device go to settings -> security -> Device administrators
2.) uncheck the box next to McAfee Innovations
this will now allow you uninstall the application.
As part of the setup flow for the Smart Perimeter feature, you are asked to grant device administrator privileges because it's what allows the feature to put up it's only lock screen. We are looking at ways to improve the ability to uninstall and make it simpler for who are trying out the features like yourself.
Do you have any specific feeback as to why you are uninstalling? Was the feature not what you expected? Did you have issues getting the feature setup? We'd love to get your feedback to see if there are ways that we can improve the product.