This is a prime example of why you have to vigorously police and defend a trade mark in order to reap the benefits from it. People complain when a large company does it to a small one, but if they don't they can easily find themselves in a situation like this.
I am currently creating my own product, and the very first thing I made was to create a new name, and claim the mark. It cost me some money, but not that much compared to the risk of being in trouble with trolls.
The sad things is that by doing this, I am probably feeding the complexity of the system myself.