[pmiller2]

That's correct. they vote to advance their own political agendas. Those agendas also correspond to those of the appointing President's party. That's literally the definition of "politically motivated." The available evidence thus points toward individual Justices being politically motivated. Occam's razor suggests the burden of proof falls more strongly on the opposite position.

[kube-system]

The available evidence, and scholarly consensus, shows they vote based on their established personal ideologies. If you are claiming it is more complicated than this, Occam's Razor is on you.