While you may (or may not) be correct in your assumptions, your tone in general is rude, and disrespectful. If you are indeed a true editor of distinct taste and experience, you should not feel the need to bad mouth others for their thoughts and opinions. Show a little decency, and realize that you are indeed speaking to a human being, who probably has thoughts and feelings, and is in my opinion, a much more intelligent human for having the intellect to not attack someone verbally for their thoughts. No one needs you to be rude, or asked you for that matter.
You might hire someone for a proofread, but let the editor know that you’re open to hearing from him or her if the work needs a heavier edit. The editor would need to present you with evidence in the form of sample pages that showcase what’s needed—and your job is to make sure you agree. You want to feel like an editor’s edits are polishing your work and making it shine. If you feel dread or anger, or even if you feel misunderstood, it’s likely not a good fit. At the very least you want to share your reactions with the editor so they can respond or change course.
The romantic myth of an author sitting alone in their room and emerging with a finished book is just that: a myth. Writing is a tough skill to master. Good books are the product of talent, craft, revision and more revision. Like all creative arts, writing requires critique from knowledgeable professionals who can make suggestions and provide direction from a perspective most writers can’t obtain on their own. From developmental editing — with advice on story and structure — to copy editing and proofreading, working with a range of book editors is absolutely crucial when writing a book. But where can you find the professionals with the right experience in your genre to take your story to the next level?
Obviously there is a big difference. I actually started with screenplays (with some mild success) partly due to hearing that as long as you have a good story, the grammatical errors won’t be a big deal. Well, that was not true. Maybe if a producer liked the story or I was already established but every contest I entered always came back with feedback about the grammatical errors. Even if I won or placed as a finalist, I always received critique on that. Very little is spelling error, it was more about structure, etc.