So, fandom is something to be enjoyed by all. I don't care if you hate certain ships or characters, the point of fandom is to be able to freely enjoy the material.
Given that, I feel like it needs to be addressed that fandom etiquette has been lacking.
If you dislike certain aspects of a fandom, block those tags. Along with that, do not use those tags to talk down on those who enjoy those aspects. There are often specially curated tags for disliking those aspects (e.g. people tend to use "anti [aspect]" to do so). Those people are allowed to have their community, but if they start hogging the non-anti tag for said aspect, then it becomes an issue.
I know some people do not believe in pro-shipping (which just means one is for the freedom to ship, no matter how controversial it may be, and not problematic ship), but that dislike will lead to furthering censorship--one of the main enemies of fandom as a whole. You are allowed to disagree with certain things, but you have to understand the consequences of being anti-ship and what that may bring to fandom.
Furthermore, don't publicly post about hating a fic. If you don't like it, talk about it privately with friends, or don't talk about it at all. Fanfic writers do not write for you; they write for themselves. You actively bashing what they love dearly just makes you a dick, not someone spreading goodness.
Also, for the love of fandom and human society in general, do not go around spreading hate to creators in general. There are people behind the screen. You do not need to agree with them or things they may have done, but a public witch hunt will get you nowhere. Things that you believe to be true can be easily doctored. The internet has existed for some time, and even history has been doctored.
Block things you don't wish to see (e.g. characters; fandoms; ships; creators; i don't care). You are the only one who curates your page. Tumblr is special that way.
You do not get the excuse to yuck on someone's yum. That makes you part of the reason why fandom has grown to be toxic. You are not some saviour for doing that. You are actively contributing to the problem.
The want of fandom is to create a positive space, so just think for a moment if what you are doing will create a positive impact for the fandom, or if you are actively feeding into the negativity and making it feel like a genuinely unsafe space.
We are all people. Treat everyone with respect and try not to be a total prick.