This is understandable and, more often than not, forgivable. After all, there is much to bitch about. Writing is tough; getting readers to buy and read your material, even tougher.
Having said this, I can't understand writers who do nothing but whine and moan about the misery of writing. I just don't get it. If hardship, toil, and misery is all you experience when you are writing, you are doing it wrong, and you should seriously begin to question whether you should be doing it at all.