Because the XT stands for nsa-eXTensions.
   No really, Hearn is a joke, has been consistently working to weaken
   bitcoin since 2013.
   In any case nobody gives a dime about XT:
   [1]https://bitbet.us/bet/1191/the-hearn-gavin-scamcoin-will-fizzle-in-2
   016/
   But they are still trying to push the hardfork and other assorted shit
   in BIP100/BIP101 etc.

   On Tue, Aug 18, 2015 at 11:07 PM, grarpamp <[2]grarpamp@gmail.com>
   wrote:

     [3]http://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-Augus
     t/010379.html
     [4]https://github.com/bitcoinxt/bitcoinxt/commit/73c9efe74c5cc8faea9
     c2b2c785a2f5b68aa4c23
     Bitcoin XT contains an unmentioned addition which periodically
     downloads
     lists of Tor IP addresses for blacklisting, this has considerable
     privacy
     implications for hapless users which are being prompted to use the
     software. The feature is not clearly described, is enabled by
     default,
     and has a switch name which intentionally downplays what it is doing
     (disableipprio). Furthermore these claimed anti-DoS measures are
     trivially bypassed and so offer absolutely no protection whatsoever.
     ...

   --
   Brenda Fernández
   [5]me@brendafernandez.com
   GPG: [6]CE5BEE6C81FCA4D4

References

   1. https://bitbet.us/bet/1191/the-hearn-gavin-scamcoin-will-fizzle-in-2016/
   2. mailto:grarpamp@gmail.com
   3. http://lists.linuxfoundation.org/pipermail/bitcoin-dev/2015-August/010379.html
   4. https://github.com/bitcoinxt/bitcoinxt/commit/73c9efe74c5cc8faea9c2b2c785a2f5b68aa4c23
   5. mailto:me@brendafernandez.com
   6. http://pgp.mit.edu/pks/lookup?op=get&search=0xCE5BEE6C81FCA4D4