The fan sign was under Hybe Labels Japan and arranged by that specific label. New Jeans is under Ador... If you were going to boycott something, it would make more sense to boycott Hybe Labels Japan. The group who this fansign was for is a rookie group that debuted in December. They don't have millions of dollars or a very big fandom and they're still building a presence in Japan and Korea. A boycott would actually harm them a lot and that's not something Luné are considering at all. Our fandom (Luné) is addressing the issue.
Edit: HLJ sucks ass, so I'm not surprised they found a new way to suck even more.