To spell or not spell?

A number of times on Biz Community, I have commented on people's appalling spelling and every time people react like I'm some sort of evil pariah. Everyone makes mistakes, as do I. I have sent out press releases and submitted comments with errors. What I don't think is acceptable is some of the garbage we send out and then expect clients and the media to take us seriously as an industry. Some of what we send out would make a grade 5 pupil blush. Most of the spelling errors I see could easily be corrected with a spell check available on every computer, so I can't believe this results from anything but laziness. My many questions are ... Am I missing the boat and is it ok for us to send poor quality out? Why do we complain that we're sometimes treated like airheads if we ourselves seem to condone lack of effort? Would we take an accountant who presented blatant errors seriously as a professional? Don't we think our clients, the media and our peers deserve more?