@essen46 mangakas been using over the top bullying just because it's a popular trope. over the top bullying exists, mind you, but mangas normally use it because it attracts attention. It's similar to the increase in monster girl mangas or isekai novels/mangas, and many times editors even ask the mangakas to put such elements in. To compare to western media, that time when all comics wanted to be wolverine with high violence tuned to 11 or the time(s) everyone wanted to be batman with the "totally dark and serious, no fun allowed" boom.
A fair amount of mangakas likely don't want to do it, but many of them are new to the job and so first need to get a good run before they are allowed more control on their desicions because no one likes to risk losing their jobs.