I think that in the end it does not matter, anymore. It is inevitable that most of the text now and in the future is at least reviewed by LLM.

We should criticize whether text is poorly written, inaccurate, wastes words to get to the point and anything like. Saying that it is "written by LLM" just bypasses this and is not useful and misses the point. AI written text can be really good if used correctly. Criticize the content, don't speculate how it was written. If AI helps us to write better text, that is great. But often it is not good.

It is better blame the author for the bad text, so they get consequences and might do better next time, if the text is bad.

By the way, I think this piece of text was quite good.