First of all: fandom wank. I want to douse it with gasoline and burn it dead, dead, dead. I know it's not possible because too many people thrive on drama and spewing hate on other people but dear gods do I wish it gone.
Let's look at some ways to reduce this problem ...
* Understand that cyberspace is like the Jedi Tree. It contains only what people bring into it. If they bring wank, there will be wank; if they do not bring wank, there will be none. Fandom wank does not bring itself. People do that.
* In any space you control, such as a blog or a website, you get to set the parameters. Think about what you want to do there, what you want to avoid, and what will facilitate that. Tell people your expectations so they know what is acceptable or not in your space. Don't like wank? Say so in your profile and/or sticky post. Then be prepared to warn people if they cross a line, or ban them if they won't quit causing problems. I've been doing this for decades, so here are some of my previous posts on the topic:
Sample Online Community Parameters
Civility in Blogging
What Makes a Community Successful
* What is your blog metaphor? This influences how people choose to behave. Mine is basically an analog of office/living room, which is how my house is arranged: my office is adjacent to the living room. I do also hold a street faire in my blog every holiday season; see Winterfaire 2019 for an example. Even though the venue remains the same, the metaphor and thus the activities change.
* Regarding venues that other people control, choose ones whose parameters agree with your personal principles and desires. If you don't like someone else's rules, don't go in their space. Assholes need places to hang out with their asshole friends so they don't bother other people who dislike obnoxious behavior. If you don't like the people in a venue, don't go there. You should also look for strong moderation controls. You need a way to shut out trolls if they find you.
* Do not feed the trolls. If someone posts falsehoods, or an attack, or whatever, responding once to correct the nonsense or state that it is unacceptable is sufficient. You won't convince them, but the accurate version is now available to anyone else who reads it. After that, ignore them. You can also ignore them altogether, as many people do. Shouting into a void is boring; if everyone ignored trolls, they'd go away. It doesn't work well in person, but does work better online, especially in a venue that lets you block people so you don't have to see them anymore. If you control the venue: banhammer!
* If you are attached to a venue with poor moderation controls, and people harass you on it making it not fun, leave for a while. Close the window, go to another venue or work offline, shut off your computer and go outside. Do whatever works for you. Give it a rest for a few hours, a few days, or a few weeks. The modern attention span is short. Soon enough people will go haring off after something else and you can resume your usual activities. However, if you often have problems on a given venue, do try to find a replacement with better tools for preventing abuse.
* There are various ways to deal with wank in progress.
** Point out the bad behavior and what better behavior would be.
** Report actionable incidents to a moderator for warn-and-ban handling.
** Provide an alternative in the same venue. Master pacifist Suzette Haden Elgin recommended posting recipes. I tend to prefer using something that is on-topic. An excellent response to fandom wank is posting links to fanworks with positive character interactions.
** Invite the civil members to a conversation in a venue you control, so you can block the trolls from following.
* If you don't see an online venue that does what you want, make your own. This can be a blog, a website, a server with robust hosting, whatever. Everything you see on here, somebody made. So if you think, "Somebody should do something about this," well -- be Somebody!
* Another way to minimize fandom wank is to seek out facetime connections instead of or in addition to online ones. People will say and do things online that they are much less likely to do in person. While facetime fandom is a lot rougher than it used to be when it was small and close-knit, it is still politer than online fandom on average. Manage your energy at conventions. Be prepared to accommodate special needs at an event.
* Be the change you want to see in the world. If you don't want fandom wank, don't write or link fanworks with that kind of tone where characters pick on each other, ignore boundaries, and act awful. Write and share fanworks where characters act the way you wish more people would act. This is especially true if you're writing heroes. So much of canon today is, in my opinion, unheroic and obnoxious. I don't want to watch entertainment where the only difference is the color of the costume, if that. I've seen shows where I couldn't tell from a glance what the sides even were, because the characters all acted and dressed similar. I think we need heroes to show us that nice isn't boring and doesn't make you a doormat. Gentleness is controlled strength. So if you want genteel fans, give them genteel heroes, and stand up to that principle even if the bigwigs are determined to drag everyone's cape through the mud. I believe that we can choose to be better than a pack of monkeys pulling each other down.
* Be kind and encourage others to do likewise. Just because pigs like mud doesn't mean you have to get in there and wallow with them.
* If you upset someone, apologize. If it's a big issue, make that a concrete apology.
* Teach peace skills. Demonstrate them. Some people are obnoxious because they were raised by jerks and don't have any other tools. That is a fixable problem.
* Improve your conversation skills. Most of them work as well online as in person.
* Teach emotional first aid and promote its use. You can help online friends through difficult times, even if you can't be there in person. Do you see fandom wank attacking someone else? Stick up for them, it matters. Be an upstander! "I can do this all day."
* Understand how to cope with stressful situations and emotional drop. Fandom wank is stressful. Coming home from a convention or walking out of an online venue can cause emotional drop. You can handle this stuff.
* Make a self-soothing kit and use it when people are mean to you, online or in person. If you scraped your knee, you'd know to go wash it and wrap it, right? The same applies to emotional injuries, only people aren't taught how to treat those, they're taught to ignore it. So then things tend to get worse instead of better, and someone who gets picked at all the time winds up with a serious mental injury or illness. This is part of good self-care.
* Know how to deal with unfortunate results of people being mean: stop your brain from looping, deal with going nonverbal, or connect with your environment as needed.
* Don't worry about what people think. Don't let them shame you. You deserve to be treated with respect. Insist that people do so.