@corlin exactly
It isn't that hard or even time consuming to edit they phrases out I'd recon the "papers" that don't are deffo "bots" being used to auto generate them and maybe post them as "papers"
And like you say a lot will be getting edited as well taking they phrases out - there are tools though available that will determine if something has been AI generated - Tools like Copyleaks and AI Text Classifier are over 90% accurate and have proven fruitful in identifying AI-generated content
@ecksmc
These folks, or bots, or whatever, aren't even trying hard to edit, or disguise what they're doing.
So can you imagine how many there are that do light editing? Many, many more.