A lot of it has to do with putting the head gear and gloves on that are required by the rules of the competition..how can you use a style that relies on having sensitivity and such distinct hand positions when you wear gloves? Everytime you get people wearing gloves you'll get people doing like the guy in the 3rd? video did - WC guard and then straight into kickboxing with a bit of judo thrown in. They're not doing the wrong thing, they're doing the only thing they can in the circumstances.