What's With All The Misspelled Words?

I'm surprised at how often I find missing or misspelled words in posts from magazines such as Inc. and Business Insider.  I've even found them in New York Times online articles.  What's going on here?  Certainly a computer spell check/grammar check would catch at least some of these mistakes.  Is it no longer necessary for professional writers to write correctly?  Is there no pride of workmanship in these organizations?  Are these articles rushed to publication too quickly?  Whatever the cause, it's disturbing that this is level of professionalism is acceptable to organizations that deal in the written word.