According to most commenters on Internet forums, grammar and spelling are unimportant and for the most part should be ignored. And anyone who complains about such errors, intentional or otherwise, should be hung by the testicles until shriveled.
Public school education is the problem. Teachers are unfamiliar with the subjects they're trying to teach (such as reading, writing, English).
When a person is corrected by the "language cops" he is embarrassed and his only response is name-calling.