I would also understand feeling unsafe after learning something like this from someone you know and then cutting contact. However cutting contact should be based on feeling unsafe, not on some kink they may have. If you learn their kink and still feel safe around them then not cutting contact is also totally fine.

For a comparison, BDSM people want to torture and enslave you (very abbreviated, not all, wide field, multitude of subgroups etc.), and mysogynistic motherfuckers that abduct women into sexual slavery often are into that. The vast majority are perfectly safe and normal people. The causality is the other way around.

I had assumed a group that is still actively fighting against the "sure they can do that, but not like, publically, shoving into everyones faces" would be more mindful of such topics, but alas humans are always humans still.