@deathmailrock I don't find that analogy fitting for the situation. You keep downplaying the level production in contrast to criticism. If anything this is like a person saying they love Italian Restaurants or like eating at them, but the ones they keep finding can't even boil pasta. This isn't one small instance, this isn't one small manga being bullied in a corner. It's thousands of manga flooding the market. They do not have to be the only kind of Isekai to be a problem, they just have to be over-represented, oversaturated, and overdone.
So here's a little fact that I've come to realize over my life. The people who watch and read these things? They tend to be the ones FULLY aware of how bad the stuff they consume is. Go and read some of the comments on this site, you'll find people calling the story garbage but with the context that it's garbage they enjoy. For them it's just junk food. They know it's overdone, they know it's cliche, they like it anyway and don't pretend. Nobody watched Interspecies Reviewers and thought "This is an anime of class!"
Also I find it weird that you keep bringing up insults towards the readers of these genres. While it isn't something I would do and don't think it's something anyone should do, I find it strange because that isn't the topic we're talking about. We're talking about a genre with a bad habit of excessive repetition and little innovation. If a form of media exists, no matter how big or small it is, and continues to repeat itself without any real innovation in the name of a quick buck, it absolutely deserves to be criticized and neither I or you hold the right or authority to tell someone they can't criticize it. A person does not need permission to criticize something. If the criticism itself is repetitious then that simply means the problem hasn't been fixed. The amount of time between when the criticisms start and when they end means nothing other than acting as a timeline for when the problems were first noticed to when they were solved.
These problems have not been solved. In fact I've seen more and more Isekai manga mocking the isekai genre itself for being so repetitious (quite a large number of Isekai even reference Isekai as the basis for their knowledge of what's about to happen), meaning the authors themselves are fully aware of the quality they're putting out. This oneshot is just one representation of a larger reaction within the community both close and abroad. That reaction is simple: If all the stories are the same, then the story is no longer interesting. Monotonous ideas are not interesting to people and if they become the representation of your medium, genre or what have you - there is a problem.