The president does not appoint Supremes, they are nominated, only. It is the Senate which makes the appointments. Blame them for the alleged stupidities of appointments, although I see no stupids on that Bench, just variations of opinion, which is the way it is supposed to work, and does in the mid-80s percentile since the Court has overturned itself in a little less than the 15s percentie in its entire history.
So, why are Domcrats juiced up to stack the Court? Now that is stupid.
Consider that over the same history, 23% of S.C. nominees have failed to be approved by the Senate, so that piece of the puzzle is far more problematic to the Court's relative success than the common accusation that the Court is biased one way or another.
Consider that had Justice Ginsberg survived to see the Dobbs v Jackson Women's Health 2022 case, she would have likely sided with the majority to overturn Roe. She stated in public several times in her later years that she thought Roe was a flawed decision.