Earlier quoted context omitted.
This part of the editor's process bothered me, too. Overall I agree with his premise and have no problem with what he's doing. In fact, I think he is improving Wikipedia with his edits. But changing quotations seems like a step too far. I think his practice of changing a quotation to a paraphrasing (where it doesn't really matter if the article includes a quotation or not) is fine (if a little obsessive). But actuall…
Fixing "it's" to "its" transparently in many cases is one thing. More significant changes to what someone presumably meant deserves a [SIC]. Something that's not wrong but isn't your stylistic preference? No way.
“[sic]”, which is always lowercase, indicates something the current author views as (probably) erroneous or otherwise improper that is left unchanged in the quoted text, to emphasize that the author isn’t endorsing the usage/construction so marked. It doesn’t mark a change.