I think they're under-estimating Goku's abilities in this video. He has superior energy weapons while Super-man only has heat vision. He also has the Hulk-like ability to increase his power (Kaio-ken, spirit bomb, super saiyan), which Super-man can only get from exposure to a yellow sun. Writers have also taken a lot of liberties in expanding Super-man's powers over the years. Plus Goku is a martial artist, where Super-man is just a brawler. Super-man has some very specific weaknesses that can be exploited, such as his need for the sun's rays and weakness to kryptonite, weaknesses that Goku doesn't suffer from, though Goku can weaken through power use.
edit: favorite move of the fight starts @21:35.