You asked "Why not 10000, or 1999 ?", well why not 3000? Make it 10000 and very few would qualify at this time, many have made 1000 posts in a couple of months and then given up. As Des joked about we could make a section for those who joined before Dec 2008, to which I replied it was a good idea but there would only be about 4 of us in it.
If you posted 2990 jokes or even 3000 (or any acceptable off-topic post) that would still be a valuable input to the forum. You reckon you've made 1000 "quality posts" but if you want an honest answer, in my opinion your posts are often hostile and rude, hence you having been banned in the past.
I haven't posted 3000 "jokes", I have made 3000 helpful posts and I have shown that I can participate in a forum in an amiable fashion; if you make it to 3000 posts maybe you will have learned something about that by then.