I think you still misunderstood what is wrong, LWC.
I'm accused that I take others' work and present it as my own
Wrong. everybody knew that you did not take out the copyright information of the file.
I present my work as others' work
True. You did not change the names and set the version number back to 1.0. Users would download your version of the forum and think its a release from Blaine for example.
Each and every file states it's an update by myself that uses the previous work of X
Sure, as I said after the first quote, nobody doubted that. But users do rarely read the content of the files. They only compare the title of the program/script, download and install it.
"filemgmt" and especially "forum" use as generic names as they can get.
You do not have to use generic names. "google" is not a generic name. "geeklog" is not a generic name. Call it GLFiles and GLForum if you want. Finally those two plugins were the first of their kind for Geeklog, so they can have any name they want, and as generic as can be.
But this all was (as far as I can see) just a problem of you underestimating the consequences for users when there are suddenly two authors releasing plugins with the same names and similar version numbers. And this is where the GPL is in conflict with your actions. The preamble clearly states that you are expected to change the name of the software in case you redistribute it with modifications.
The point were people got mad at you was, that you, simply because you made some small changes to the code (around 1% of the code as far as I can estimate) and setup a forum, thought that the original authors would stop using their CVS/SVN systems, their forums, online help, websites, file repositories, send all their users to your site, reverse their current advances in the code to the level of the last release, take your changes blindly and accept you as the new distributor/supporter/main author of their software, on your website with political messages hey might not even agree with. All that after they have been working on those plugins for years and given support to hundreds of users. All that without you ever even talking to them about it. All that just because you thought they do not work fasst enough to met your demands.
But this is not a GPL problem. This was simply perceived as extremely arrogant.
I guess the real problem is the upgrade concept so when I fork you just wouldn't have your old data in the new plugin (until I add import ability).
Not really. The problem is that users, if you do NOT fork, will mess up their system as soon as they update your version with that of the original author. If you do fork, only you have a problem of writing a function that copies the old tables to a new name.
The biggest problem in most of these issues lies with the users. Since you did not have any users of your software (yet) except yourself, you probably did not think about them. You thought only that you wanted your register_globals off and LTR/RTL and some more add-on features. Thats also why you see only a problem in you needing to write a import script and not other users messing up their sites because you don't want to fork.