The bigger distinction is that a judges politics only matter if they are activists as opposed to originalists. So since the conservative judges also tend to be originalists, then when the law requires, they will easily vote against their political ideology - something the liberal activists are far less likely to do, since they don’t consider themselves to be as restrained by the letter, or even the intent of The Constitution.
I’m guessing it’s because the leftoid justices are group-thinking DNC party animals, while the rightward justices think and reason for themselves.