This might be "false personation" under California law. See California penal code 529.[1] This is slightly different from identity theft. It's a criminal offense. The key elements of this offense are that someone else impersonated you in some way, and they derived some benefit from doing so. Because this is a criminal offense, AngelList's TOS's arbitration clause does not apply. You can file a police report with the SFPD. If several people do that, something might be done about it.
[1] http://www.leginfo.ca.gov/cgi-bin/displaycode?section=pen&gr...