There is probably more than one reason, but I noticed a thread was started just before the crash that claims the XT Bitcoin wallet contains code that downloads your IP address so it can blacklist selected wallets. The thread OP also claims the XT Bitcoin wallet can figure out your real IP even if you connect through Tor through some clever trick.

Bitcoin XT has code which downloads your IP address to facilitate blacklisting

It could be a factor that facilitated the crash. Before I read that thread I thought the only changes in the XT Bitcoin wallet were to allow bigger blocks.