Check the name and institution. Science is done in English, but not always by native English-speakers.

The issue is by no means exclusive to non-native speakers.

Having peer-edited papers from many fellow students throughout college, I was astonished not only by the low quality of writing, but the lack of improvement from first year to graduation. Of course, it's possible that most people are simply innately incapable of writing above low standards and these students had hit their ceiling, but I don't think there's any basis to infer this given that they weren't given any instruction or pressure to improve. Grading was only influenced by fluency of writing at the very bottom end, so there was very weak selection for writing ability.

Actually, I think our education system ought to put a lot more focus on teaching to write well at the level of middle and high school. The essays students are made to practice writing are poorly tailored to cultivate the sort of writing ability that students are likely to find useful in the future, and public education generally doesn't offer students much other instruction in writing well.