To the OP, I certainly don't think anyone is taking offense at your post, and your question is quite valid. I got the impression that it is an honest question from someone who wishes to improve their language skill.
If I may, I'd like to make a case for the original users to those who do seem to get upset by examples such as these. And, perhaps give some insight into the issue.
There is official English, just as there is official German, Spanish, et. al. However, there is also colloquial English just as there is for the others, along with regional dialects. Many Americans who have travelled to Mexico have certainly encountered this when their High School Spanish collided with both!
The examples in the original post are colloquial English, and a very common divergence from proper English.
I often see people being corrected that were merely using their regional dialect, and spelling it as best they can. Other than Appalachian, and I have heard of but not seen, Cajun, there is no dialectic dictionary for them to refer to so far as I know.
American English has been classified as a separate dialect from British English, as the differences between them have become substantial enough to warrant the classifications.
American English has sub-dialects as well, such as New England, Midwestern, Appalachian, Southern, Cajun, etc. In strong cases, the sub dialect can be incomprehensible to the hearer. For example, my wife is originally from New York, and grew up in Tampa. Her parents still have a strong New York accent, especially her father who is from the Bronx. They also use the New England dialect. My Grandmother was born and raised in the deeply rural Appalachian Mountains, was primarily self-educated, and never left that area until her 70's. During a visit, she spoke at length with my wife. I had to interpret for my wife, and later re-tell some of the stories.
This is also a very good example of how languages evolve into new languages over time. English should eventually evolve into a family of languages. It will be an interesting study for someone in the future, as with the internet and fast travel, regions are not nearly as isolated as they once were. This should have a dramatic effect on the evolution of the dialects and their transition into languages.
I could delve further into the origins of the dialects, the factors that influence their progression, and so forth but that is far outside the scope of a simple forum reply. My point is simply that forum boards bring together people from all over the world, many of whom speak a regional dialect, and others who speak English as a second language. There are also varying levels of education, age, and experience. So unless an error causes the reader to not understand the message the writer intended, or perhaps to help a non-native English speaker to improve on their skills, I should think that corrections are generally unwarranted. I should also think that some of the more demeaning and insulting forms of correction that have been used by a few at times have most certainly been unwarranted.
