By the time a writer trying to find a publisher receives their twentieth rejection letter, they are about ready to make voodoo dolls of commissioning editors - those brave folks who have to decide whether or not to take on a new book. To be frank, this is an entirely understandable emotion, but it's not really fair to the editors.
Firstly commissioning editors are human beings. Really. So you have to make allowances. Secondly, although your manuscript is superb, they do receive an awful lot of rubbish, so you have to expect that they may be a little curt. Finally, and most importantly, they aren't all powerful.
In most publishers - certainly all big publishing houses - the commissioning editor will also have to do a pitch. They can't decide themselves whether or not to take on a particular book. If they love it, they then have to sell it at a meeting - and it's only if they can convince their hard bitten colleagues that your masterpiece is worth publishing that you will get that longed-for green light.
So two lessons. One, don't be too hard on the editor. Two, give them every bit of ammunition they can use in making that pitch. Ensure that your submission is superb before you send it. Of course they may still hate it, but if they love your work, they need all the help the can get.