The vast majority of what I see slung from the 2003 side is in reaction to shit from the Brohood side, because of the Brohood fans calling '03 a "piece of shit" and saying it "shouldn't have been made" and telling new fans not to ever watch it (instead of, y'know, realizing that tastes differ and trusting them to make up their own minds), or making up bullshit reasons to hate on '03, and saying that Brohood is so much better and the only one worth watching because it's the manga storyline, etc.