To answer your question, I had about 150 posts when they first began the Kumi system and I had 5000 Kumi. I believe they gave you Kumi based on your time on the base. He and I have the same amount of time when it comes to our membership on the base (Aug of 2010). I started with 5000 then, and despite his low post count, he's been a member since that time so that was his default I guess.
Also this guy seems more like a Minato hater then an Orochimaru fanatic...but I guess he's both.
I see nobody on that list who can defeat Minato. There are a few contriversial peoples (Itachi, Nagato, Madara, San-Rai) that could be argued as being able to defeat him, but imo nobody can (San-rai may be exception as I'm not sure on that one myself)
You're just a Minato hater to a high extent where you don't even give him credit. What brings me to that conclusion is one name in perticular that really stands out above all the rest "Hanzo"...Really? Come on guy give credit where credit is due.