Providing users with a free alternative is most certainly cool.
It's up to you, as a developer, to give the users a reason to purchase YOUR application with features which the other developers don't offer.
Adding people to your ignore list is obtuse, it shows you're not open to fair competition and gives the users another reason NOT to go for your paid apps.
XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. Are you a developer?