I have made this point before in disqus comments but let me make this an actual post.

Disliking certain characters is perfectly fine. Putting them in lower tiers is also perfectly fine. Even though it may be a strong word, hating certain characters is also, perfectly fine. Within reason.

Hating a character doesn't make it okay for you to mock the fans of a character

Hating a character doesn't make it okay for you to try and convince others why they shouldn't like a character

Hating a character doesn't make it okay for you to guilt others for liking a character

And hating a character never makes it okay for you to say a character should die, burn, or anything else

There are people who like those characters you may not like or may hate and it is annoying to see people say that your faves should die when a dislike could easily be expressed differently. Particularly for me who gets attached to my faves, it's upsetting to see people just say these things carelessly. It is characters like Kaoru that have made a big impact on me, especially since Kaoru was the first character that I got attached to. If you want to make a tier list or say anything about a character you don't like as much, think about how there are others who see these characters as their favourites and how there are people who may feel attached to these characters.