He has a weak base/legs. Doesn't get a lower centre of gravity. His take down defence looks iffy. There are many reasons but you are right he gets thrown around like a rag down. What happened to him recently was one of the most consistent take down, GNP performances we've seen in a while. Ortiz v Shamrock was in my head.
Yeah, because Marraro had good technique and Kongo didn't. Just as others have said here, it has to do with his balance and is center of gravity and all sorts of other stuff that guys like Velasquez and Marrero and even Herring have been working on for years. 185 lb guys pick up and slam 185 lb guys all the time, so when a 240 lb guy picks up and slams another 240 lb guy I'm not sure what the mystery is.
If if if if if. Your guy got WORKED. He landed flush and then got planted, then landed flush and in the DUMBEST MOVE POSSIBLE went for a takedown. Are we done with all this "Kongo will be the next champ" crap?