They are most likely using one of 3 options to block Tor. 1) They use Tor-provided lists of Tor exit relays 2) They use publicly available block lists 3) They rolled their own block list generator
The point is, this information is publicly available. So, the question isn't how they did it, but why they did it. The answer is whatever reason they chose. Your best option is to attempt to contact them directly and ask. Matt Speak Freely -- tor-talk mailing list - [email protected] To unsubscribe or change other settings go to https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-talk
