Say "it is my damn right to outdate my code! Just fork it if you want and stop stealing."
LWC, I think they have already said it.
As a franstrated long term GL user and non-coder, your contribution is a tremendous help. I am sure, I wouldn't have known these rules and might make the same mistake. However, like Tony said, I think you definitely need to be tactful, particularly in your expressions.
Based on my past experience with you, I know you have pure motives and sincere intention to push GL to a higher level. But you tend to express it contentiously.
The plugin owners obviously feel offended (not by what you did) by the way you did it. However, their judgement of your motive is not true.
As far as I know, the GL team does not have GL as their priority. They just work together in the GL enviroment to develop their own professional projects. That's why GL has a great deal of professional quality, but it is only a by product. Unless there is some demand (e.g. by their clients) to move their script to the next level, they have other things, including their family, to be busy with. (Not everyone is Mark Evens, who you and I know presented the most outstanding plugin and support we've ever seen in this community.)
LWC, I think you are a young single man, full of fire. I can see your vision that you want these plugins to become a team product, like the main GL script. Why don't you make it so, since they don't mind that you fork them with new names. You might even draw some co-coders to work with you on these plugins, if you set up a CVS.
Just my 2 cents.