Totally disagree that TKD is much worse. Those type of things are far and few and also seem to have more control. They are also wearing more equipment and these are a little bit older kids. Kids as small as the ones fighting in the original video at the level of Taekwondo in yours, they are not that capable. In the MMA video anybody can punch and wrestle and it seems more like a school yard fight with the only rule no punching to the face.
Good on you for thinking TKD was worse, especially when most people think it is patty cake.