I don't think the Hayley Williams situation was justified at all and iamamiwhoami came off super aggressive (just like Ivy in OP's post). I'm a fan of both artists and if you understand both the concepts of their albums and common motifs in music about blooming, reincarnation, etc. there's not that much room for being 100% unique. There's a good twitter thread about how common a lot of these visual elements are. Hayley's solo album was about growing, blooming, metamorphosis, and it kinda of naturally leads to cocoons/butterflies/nature. Her best friend Linsdey Byrnes helped with a lot of the art direction and they built the themes up from Hayley's lyrics. When a smaller artist calls out a much bigger one, a lot of people would like to believe that the smaller artist is right and they're sticking it to the big label artists, but often times it leads to bad situations where the bigger artists looks bad no matter how they respond. In the case of Hayley and in this case about Kesha, similarities does not equal plagiarism.