They're just referencing a previous ruling in which both Alito and Thomas also dissented, that basically is saying the same thing. That they shouldn't have the right to deny hearing a case between two states, because there is no other court to hear them.

They're just referencing a precious ruling in which both Alito and Thomas also dissented, that basically is saying the same thing. That they shouldn't have the right to deny hearing a case between two states, because there is no other court to hear them.