That argument can be made for virtually every piece of software. We all build on top of the work of others.
BearBlog built on top of the work of others. Now you can't build on top of the work of BearBlog.
It can and it should.
The argument is that why should I be able to use software for free but do not want mine to be used the same way?
BearBlog built on top of the work of others. Now you can't build on top of the work of BearBlog.