from what I see there are 2 solutions:
1) ban TV-proxy-as-a-service - straight up go to every representative there is and start pushing and lobbying and everything to stop spammers from distributing over non-computer devices, especially legally
2) make old commits more expensive to access than new ones. Legit users are not going to access those much, so they can pay the time. I assume diverse (unpredictable?) difficulty can also make spam pulling harder