It's hard to believe some people read/watch One Piece
The main character is someone who always smiles and tries to find the best in people, and has many friends and people who respect him
And then there's the kind of people you just described...
One Piece has so much going on in the story, that there's something for everyone. Some people get mad that they don't get more of what they want in the story. Plenty of people on this site don't care about the overall story, and just like the characters they like, and want those characters to have big moments.
Also, plenty of One Piece's big ideas are hard to get if you don't research the series, because it's just so damn big. I honestly think some people look down on Fishmen with out realizing it because of how evil Arlong was. Jinbei constantly gets downplayed, and I find it hilarious because the dude stood up to Big Mom three times, brushing aside her Soul Pocus, punching her off the Sunny, and then shoulder-throwing her in Onigashima. I had Jinbei a bit above Sanji and Zoro post Onigashima, and, sure enough, he was right around them.
With Carrot, I feel people act like because some Carrot fans are weird, like the One Piece editor who wanted to make kids with her, all Carrot fans are bad. Some of the nicest people on this site are Carrot fans, acting like someone is a bad person because they find a fictional character interesting is ridiculous. People are so used to accepting division they ignore the entire point of the fucking series, for people to come together and overcome their differences: WE ARE! I wish humans would stop hating each other over fictional characters.