I think it comes down to how both sides view impartiality. There's definitely confirmation bias when the president nominates a judge - often the candidates come from the same party so they share some broad ideological positions.

Most judges I think do see themselves as impartial jurists even if the results tend to skew toward political outcomes.

Agree it seems a bit wrong. Worth bearing in mind that cases which go to higher courts are usually ones which lower courts think aren't clear, or different courts disagree.