I like how he so emphatically says that it is wrong, and cites style guides that say it's OK to use 2 spaces.
From the HLA source he cited (http://www.mla.org/style_faq3):
"... As a practical matter, however, there is nothing wrong with using two spaces after concluding punctuation marks unless an instructor or editor requests that you do otherwise."
From the HLA source he cited (http://www.mla.org/style_faq3): "... As a practical matter, however, there is nothing wrong with using two spaces after concluding punctuation marks unless an instructor or editor requests that you do otherwise."