The link you posted did not work for me, but presume it was the blog post by the person who started on a single word .xyz, reported problems sharing link's with his wife's cell phone provider in text messages, and saw traffic increase when switched to two-word .com (that gets traffic redirected from the single word .xyz they still have). It is of course one person, and a number of businesses have operated successfully on .xyz for many years, so there may be something unique to their startup journey that reflected on that one name (just speculating).
