It's possible to be democratically selected, and still have a life-term so you can be insulated from politics. The arbitrary way that the president can select all federal judges for the entire country (to my understanding) not only skews the judicial system, it adds a whole new dimension the the presidential election which really seems to distort what the job is actually intended to be.
For example, it was the sole reason a lot of people voted for Trump: because at this moment in history there happened, through sheer chance, to be this hugely disproportionate opportunity for a party to grab power that will last a generation. Just because a bunch of people retired around the same time. And this momentous opportunity completely hinged on what would already be the most important single election in the land. That doesn't feel remotely like what the founding fathers intended.
It wasn't sheer chance. It was Senate Majority Leader Mitch Mcconnell subverting the Constitution with a coup, refusing to even let the Senate consider whether to approve Presidemt Obama's nominations. And now that Mcconnell has eliminated the principle of upholding the Constitution, we can expect the same from every Senate for at least a generation, and judges will only be appointed when the President and the Senate are the same party.
For example, it was the sole reason a lot of people voted for Trump: because at this moment in history there happened, through sheer chance, to be this hugely disproportionate opportunity for a party to grab power that will last a generation. Just because a bunch of people retired around the same time. And this momentous opportunity completely hinged on what would already be the most important single election in the land. That doesn't feel remotely like what the founding fathers intended.