It's actually a pretty cool tradition. If you look up "haka" on youtube you'll find a lot with larger groups. The guy in the foreground is on the rugby team called the All Blacks and they do a haka before each match!

I know what it is, it just looks retarded especially with the amount of energy they are putting into it

We know - did you see the post caption? The rest of the text is just for the joke!

They still need mental help in my opinion

It's a ritual that the Maori (native New Zealanders) practice. Seems rather insensitive and ignorant to condemn a harmless tradition just because it looks weird to you.