dude, im gonna tell you this the good way. this is itf taekwondo and the right en first way of real taekwondo, the reason you considered this for WTF taekwondo is your own fault of unknown. dont think youre a professor with that way of talking with conclusions. sorry for my bad english
In many countries in Europe, there are no belt divisions in sparring if there is a minimal grade required (say 4th Kup and up), or there are only two, say up to 5th Kup and 4th Kup and up. So it's normal for red belts to compete against black belts.