I can't find in myself to justify them honestly. Character replacement it's something that happens. If one is an older reader must know it, it's one of the tropes, it comes with the genre they say to love. I can understand cancelling the books from the pull list, sure, it's stupid to read a book one doesn't like. I can understand for a new reader to be sad his favorite character is dead, because he could believe he won't come back. But the outrage, the constant whining, the attacking the new characters with insults and silly criticism based on nothing, especially when I must read it everyday if I want to browse a comic forum, it's unbearable and frankly in bade taste.
What's the meaning of saying stuff like «Riri as a character is nonexistent»? It's as much «existent» as Peter Parker was after 5 issues of Amazing Spider–Man. Actually it already has more layers and development than Parker after 5 issues of Amazing Spider–Man. This idea that a character must wait years before taking the place of an established one is delusional. It's fiction it's not the military. A character doesn't need to «deserve» to be a legacy hero, its predecessor is a fictional character, it never did anything, writers invented stories about him, that's it.
Any hobby has its share of fanatics. And they all act the same. They are self-entitled. They live under the impression the hobby is «their». That they are more important, or care more about it, than new fans. That they understand it better. And, that's the final stage of this disease, after a while that they have their hobbies, they become delusional enough to think they know better than who actually does the stuff. I am sure that all the comics fanatics think they could be a better EIC, or editor or writer that who actually manage, edit and write comics. Despite not having never did something comparable, knowing nothing about the actual profession, the market, the intricacies, the obligations, the politics and so on.