It by no means diminishes the magnitude of the list, but it's worth noting that the list is heavily bloated because any person with multiple aliases or whose name can be spelled in multiple ways (e.g. due to differing romanization systems) will have a separate entry for every known alias and spelling.
From the original Daily Dot article:
> The list, according to crimew, appeared to have more than 1.5 million entries in total. The data included names as well as birth dates. It also included multiple aliases, placing the number of unique individuals at far less than 1.5 million.
> On the list were several notable figures, including the recently freed Russian arms dealer Viktor Bout, alongside over 16 potential aliases for him.
> The aliases comprised different, common misspellings of his last name and other versions of his first name, as well as different birthdays. Many of the birthdays aligned with the recorded date Bout was born.
https://www.dailydot.com/debug/no-fly-list-us-tsa-unprotecte...
So there aren't 1.5 million people on the no fly list, but there's still a hell of a lot of people to ban secretly and arbitrarily from flying with no clear justification given and no clear way to get off the list.