Basically, Substack hosts newsletters that promote white nationalism, explicit antisemitism and pedophile rings. The CEO of Substack says he doesn’t want to be the arbitrator of the truth and says Substack’s “hands-off” moderation is sufficient. However, it also inadvertently provides a safe space for said groups.

sources:

https://www.theguardian.com/media/2026/feb/07/revealed-how-substack-makes-money-from-hosting-nazi-newsletters

https://arstechnica.com/tech-policy/2025/07/substacks-nazi-problem-wont-go-away-after-push-notification-apology/

https://www.theatlantic.com/ideas/archive/2023/11/substack-extremism-nazi-white-supremacy-newsletters/676156/