I have encountered only one scheduler who I think hates shoppers. I think that person hates everyone, themself included.
Just as the quality of shoppers varies so too does scheduler and editor quality vary. A small handful are excellent. Most are decent. What I don't appreciate are editors who either make up guideline rules or simply have poor English language skills.
A few editors have misinterpreted guidelines. On a couple occasions, i successfully brought editors to read guidelines as I had. On other occasions, I escalated escalated issues and prevailed.
A few editors have taken issue with my "invention" of words. I send send links to the OED or other quality dictionaries and won my case, sometimes with a thank you or an apology but often without a remark.
My very favorite involved a narrative which guidelines instructed to be "thorough and detailed covering every aspect of the encounter." After submitted what I considered a concise 2.5 page narrative meeting that instruction, I learned that to that particular MSC a thorough and detailed covering every aspect of the encounter was one which was not more than a paragraph in length with sentences being brief - ideally not more than four words in length, without compound sentences, written with passive verbs rather than active verbs; the use of commas, semi-colons, dashes, brackets, braces, and colons were a big no-no.
The best are those few MSCs which wish shoppers to go above and beyond the guidelines and to including bot subjective remarks and the shopper's own analysis. I know of not more than three which do. In each case, they pay substantially more and are more (sincerely) appreciative.