The answer is yes and no. How's that for clarity!
When I chomp on queries here, I can't point out every single mistake on the first bite or it would be overwhelming for both the writer and the Shark.
I do expect the writers to be able to identify and fix errors in punctuation or grammar. I expect them to develop an ear for awkward sentences. I think each writer has to be able to do this without help (for the most part.)
That said, it's always a good idea to have a proofreader.
If we're talking actual queries I don't overlook those mistakes AT ALL. They are HUGE red flags for the project being queried. If you make mistakes in your query you'll make mistakes in your novel. I can't submit an error-ridden novel to an editor. Well, I could but I flat out refuse to do so. My clients understand this and turn in manuscripts that may need revision and editing but generally have all the spelling and grammar correct.