Not everyone has a masters in english. Not everyone is awesome with spelling or grammar. Is it some way of making yourself look better than the next person?
What an awful attitude OP. Why would you need a Masters in English to know the basics of spelling and grammar rules that are taught to you in the 11 or more years you spend in full-time education? And why should you consider it a way of making yourself look better than someone else? How difficult is it really to learn these basic rules, such as capitalising the letter "I"?
I have foreign friends who have never been to university who write better in English than many native speakers. Why you would object to writing correctly in your own native language, I do not know. These rules are very easily learned with a tiny bit of effort.
Obviously people who suffer from dyslexia and the like are excepted, and I don't even mind people who wright in their own dialect (because its grammatically correct for that dialect). Its so bad now, when I am marking Masters papers, I get students who do not know which words to capitalise, how to use paragraphs, the difference between "their" and "there", etc.. Its actually a bit of a running joke with my Dutch friends about how badly the British cannot spell in their own native tongue.
I'm sorry, but if you have recieved the benefit of a full-time education, and are not dyslexic and do not have any other condition which explains it, the reason you cannot write well in your own native language is most likely because you couldn't be bothered to concentrate at school, spent your time disrupting the rest of the class, and so on, and now its catching up with you.