As long as you are citing that article, did you read the comments which partially explains why "defragmenting" flash memory does nothing useful? Especially the last comment, where the article's author admits: "Thanks for clarifying again. I’m still messy on blogging especially on my own articles."

The other reason that is rarely mentioned or noticed is that flash memory with "wear leveling" fragments itself on purpose and there is nothing the OS or any application can do about it. Because the flash drive is always changing the mapping of the order of its sectors, all "defragmenting" does is change the fragmentation pattern to a different fragmentation pattern, which is likely even more fragmented.