Apparently, like Disney wanting a trademark on the phrase Dio de los Muertos, Fox wants nothing else to exist that might confuse people.
It would be laughable if it weren't for the fact that to file a DMCA takedown notice that the filer must affirm under penalty of perjury that all the facts are true. Considering that there is no way Doctorow's book could be confused for the TV series, that person committed perjury because they clearly had no clue.
http://boingboing.net/2013/04/22/fox-sends-fraudulent-takedown.html