It gets confusing because people seem to use the word in different ways.  At protocol level, "dust" means an amount of 546 satoshis or less, or 294 satoshis if using SegWit.  But some people use the word colloquially to simply mean "a small amount".  But then it becomes a question of perspective.  What one person may consider an insignificant amount, another person may see as a sizeable amount of wealth.  And because this article is talking about significant sums of BTC, muddying the waters by using the word dust isn't helpful for ease of understanding.