The editor is often not the right person to decide based on technical details. Most often, articles they receive anre outside their field of expertise and they don’t really have a way of deciding if a section is comprehensible or not. It’s very difficult for an outsider to know what bit of jargon is redundant and what bit is actually important to make sense of the results. So this bit of readability check falls to the referees.

In theory editors (or rather copyeditors, the editors themselves have to handle too many papers to do this sort of thing) should help with things like style, grammar, and spelling. In practice, quality varies but it is often subpar.