Obviously there's technique to it, it wouldn't have survived as a competitive martial art otherwise. But the Japanese watch sumo for cultural reasons rather than because of their passion for the technique. It has a place in modern culture that links Japanese people to their deep-seated traditions. It's like someone uninterested in sport knowing who's playing on a given weekend, so they can comment on it as a neutral topic of discussion while getting their hair cut.
Doesn't mean that it's not a crock of shit. And I'm not saying boxing isn't exactly the same either. Sumo is just more of a traditional practice akin to ritual than it is to actual sport or martial art. But I don't know why I'm bothering to reply, since apparently none of this matters to you because your opening sentence demonstrates you don't know how to structure an argument without alienating your interlocutor.
That's the... first... thing... that's... ever gone wrong.