As we pointed out, it turn out that the warning wasn't a mistake.
TOPANGA has confirmed that "TOPANGA World League is not available in outside of Japan."
We suspect that the decision comes from Niconico side, since they co-organize the league, and earn estimated 30% of the profit. They want to block the foreign pirates who are immune from legal actions.
Now the next question is does that mean TOPANGA League won't be available outside Japan forever?