Before I comment on the topic, let me explain that I will be doing so "generally", and not "specifically" about anyone here. For every issue we encounter in life, there are usually a bunch of occurrences that should have been handled better, but there are also always reasons why some of the issues couldn't be.
For example, I ran registration for kids for a local sports league - a huge percentage of parents were always late singing up. One individual had complications from her pregnancy, many more were registering 5-year olds and had never heard of our league, and still others moved in after we started. Those are good reasons, the rest, well I used to say that I could excuse a handfull of mistakes, but not 30% every year!
So on topic, it really annoys me how so many people don't take the time to write correctly. Unfortunately that includes teachers! So as bad as it is today, the future is going to be far worse. For every good teacher there seem to be dozens more that absolutely don't care to do it right themselves. I know of people who missed questions on a final because it was numbered wrong! I have seen teacher's comments in newspapers defending their profession, with obvious spelling and grammer errors. We all see people who can't be bothered to turn off caps lock.
This site seems far better than most I come across. I take it that most people here, if not all of them, try to get things right. It doesn't surprise me in the least.
Now back to my original point: Of all the errors made on this forum, most of them had no valid reason behind them. Some of them did, but not all. We can all improve by taking the time to check our work, whether spelling on a forum, or coding in a database.