I think the point made by user jbattle is that physics already allows, for example, causal relationships that go either “back in time” or “faster than light” fr

I think the point made by user jbattle is that physics already allows, for example, causal relationships that go either “back in time” or “faster than light” from certain valid reference frames. Physicists have found ways of coping with this reality. Why should the introduction of a time machine make it fundamentally any different?