In that article, Ken is referencing the original Universal Wrestling Federation, and NOT the later group under only the initials UWF. However the footage in question is from neither anyway... it is from the P.W.F.G. There is no mention of Ken of those fights being staged, because they weren't. Again, he is referencing the first incarnation of 3 groups total who used the initials "U.W.F.", the Universal Wrestling Federation, the "UWF", and the Universal Wrestling Federation International (UWFi).
According to official MMA statistics from mixedmartialarts.com, fights from New Japan, which was famous for doing worked matches throughout their history, are included in several fighters histories of wins and losses, such ast Josh Barnett, as recently as only a few years ago.
http://www.mixedmartialarts.com/mma.cfm?go=stats.fighterDetail&pid=8286185FC8D231A9
So using your logic, are all of Josh Barnett's fights staged? And Bas Rutten's? And Ken Shamrock's? And Bart Vale's? Just because some statistic gathering groups haven't included all fights since the beginning of time, or more importantly since the UFC I, doesn't mean they didn't happend and doesn't mean they weren't real.
The fights look different from the later mixed martial arts matches in America because it was using different rules, and at a different time.