Comment by mmbleh

IPv6 is very difficult to implement and enforce reliable rate limits on anonymous traffic. This is something we've struggled a lot with - there is no consistent implementation or standard when it comes to assigning of IPv6 addresses. sometimes a machine gets a full /64, other times a whole data center uses a full /64. So then we need to try and build knowledge of what level to block based on which IP range and for some it's just not worth the hassle.