If one lives in an English-speaking country, is there really any excuse to use poor spelling and grammar?

I think that your complaint is directed toward the young. Based upon my observation, the young do not have thoughts to communicate - they only have primitive actions and reactions to primitive things. No doubt I was the same at their age, but the only means of non-verbal communication that I had was a letter. It was a time-consuming and pains-taking activity that forced better English upon us. As Marshall McLuhan said, "The medium is the message."