Understandable..
It is understandable that website operators will want to protect themselves from attack. When 100% (or near enough) of traffic from ToR is malicious then it seems reasonable to assume that you treat that traffic as though it is hostile.
It is a shame and operators are aware that it inconveniences the (potentially tiny) group of legitimate users who use ToR, but until there is universal support for the evil bit then you have to use imperfect methods to identify potentially damaging traffic.
Similarly, many sites choose to blacklist traffic from certain countries, as none of their users live there and all such traffic is hostile and unwanted.