Grammar and the job market

In an article in the Harvard Business Review, Kyle Wiens explains why he won't hire people who use poor grammar. The article begins:

If you think an apostrophe was one of the 12 disciples of Jesus, you will never work for me. If you think a semicolon is a regular colon with an identity crisis, I will not hire you. If you scatter commas into a sentence with all the discrimination of a shotgun, you might make it to the foyer before we politely escort you from the building.

Read on to find his reasons.