Welcome to GPLDL - we are still beta - please report any bugs via the contact form.
I was going to ask the same thing. :)
Why not just use their Upvato? The automatic uploads are directly from their accounts. Nobody is going to turn over those accounts because they have clients that they have to support.
Most people who get these GPL plugins do it to test them out and then buy them from places like Envato. This is because is the only way people can test them out to see if it works as its supposed to.
Sites like this are great to actually see if the product works or not. This site has actually increased my purchases because I can totally recommend a plugin or theme to a customer without getting burned with a plugin or theme that does not work for the customer.
On the other hand, while this is a great repository, a lot of plugins here are outdated, some by a year or more. You could increase the amount of contributors and verify that the code has been untouched.
WPMUDEV for example, hardly ever updates their plugins. Yet some of the ones on here are obsolete and broken because they have are far behind the current release.
Theme and plug-in settings are stored in the database. Almost all plugins and themes keep all their settings upon deactivating and removal. In fact, removal just simply removes the files.
Plugins like iThemes Security, JetPack and WP Super Cache do partial database pruning because they need to or they will break the installation if they do not remove those modifications upon removal. However, most plugins do not do anything to the database when deactivated.