Jiraiya was a serious shinobi with a certain code. Fanfiction might play around with that code too much for his liking. It could make light of things he held in high regard, like his loyalty to the Leaf Village or his training of Naruto. So that's a possible reason for his hatred.
Perhaps Jiraiya hates Naruto fanfiction because it can be very self - indulgent on the part of the writers. They might create scenarios that are only for their own amusement and not in line with the spirit of the Naruto world. For instance, they could make Jiraiya act in ways that are completely out of character just to fit a particular plot. This deviation from what he really is could be why he has such a negative view of Naruto fanfiction.
One possible reason could be that in the fanfic, Jiraiya might have made a decision that Naruto strongly disagreed with, like leaving him alone at a crucial time for a long mission. This could make Naruto feel abandoned and thus start to hate him.
One possible reason could be that in this fanfic's unique plot, Jiraiya might have made a decision that Naruto strongly disagreed with. For example, Jiraiya could have been involved in some political intrigue within the ninja world that Naruto thought was against his ideals of justice and peace.
One reason could be that it doesn't respect the original story's intention. The original Naruto story is about growth, friendship, and ninja skills. Harem fanfiction for Team 7 just throws in romantic elements that Naruto may find disrespectful to the real story.
One possible reason could be a misunderstanding. Maybe Naruto overheard some false information about Jiraiya and Tsunade that made him think they had wronged him or someone he cared about. For example, if he heard they were involved in a plot that led to the death of a fellow villager, it could turn his feelings sour.
Perhaps Naruto blames them for some of the hardships he faced. Maybe he thinks that Jiraiya wasn't around enough when he needed a mentor, and Tsunade didn't do enough to support him in certain situations. This could lead to feelings of resentment and hatred in the context of the fanfiction.
Perhaps Tails feels that fanfiction undermines the hard work of the original creators. He might think that the official story should be the only source of information about him and his adventures, and fanfiction is an unwanted deviation from that.
One possible reason could be the way the villagers treated him as a child. They ostracized him because he was the host of the Nine - Tails. He was often alone and looked at with fear and disdain, which could have gradually built up his hatred.
One possible reason could be that the council often restricts Naruto's actions. They might see him as a potential threat or a wild card due to his Nine - Tails power. So, Naruto, being a free - spirited person, would naturally hate being controlled by them.
One reason could be that he was treated unfairly by other shinobi. If he was constantly looked down upon or discriminated against by his fellow shinobi, it might make him develop a hatred for them.
One possible reason is that Naruto is so focused on his ninja training and his goals in the shinobi world that he views Christmas as a distraction. He might think it takes people's attention away from more important things like self - improvement and protecting the village.