Can career choices of a Justice's children make the Supreme Court look partisan?

Tony Mauro has an article reporting that Justice Alito's son is going to work for Senator Portman (R) on the subcommittee on investigations of the Senate Committee on Homeland Security and Governmental Affairs. In Mauro's article, Norman Ornstein suggests that this makes the Supreme Court look partisan:

Alito's move drew criticism from American Enterprise Institute scholar Norman Ornstein, who tracks Congress and U.S. politics. "For a court that is struggling for tangible reasons not to be viewed as partisan like every other institution in Washington, I wish it was not so," Ornstein said. The Senate subcommittee on investigations, Ornstein said, "has a pretty long history, mostly distinguished, as the main investigative body of Congress." With the new Republican-led Congress scrutinizing a Democratic president, Ornstein said the subcommittee may become a partisan weapon. "We shouldn't condemn the children of public officials to a life of deep constraint," Ornstein said. "But given everything else, given that Justice Alito is consistently partisan, it's just another little chink out of the court's armor."

I don't get this. I understand concerns that the Justices themselves are partisan. Maybe they are and maybe they're not, but certainly the perception is there. But even assuming that, how do the career decisions of a Justice's adult offspring make the Court look partisan? Justice Alito's son is around 29 years old, I believe. His choices are pretty clearly his own, not his father's or the Court's.

Consider Thurgood Marshall, Jr., the son of (you guessed it) Justice Thurgood Marshall. Marshall Jr. graduated from law school in 1981, clerked for a judge, and then worked for a succession of Democratic Senators and Democratic political campaigns at the same time that his father was serving on the Supreme Court. From his wikipedia page:

[Marshall] served as a Counsel to Senator Edward M. Kennedy with the Senate's Judiciary Committee; Counsel to Senator Ernest F. Hollings and Senator Albert Gore Jr. with the Senate's Commerce, Science & Transportation Committee; and Counsel to Senator Albert Gore Jr. with the Senate's Governmental Affairs Committee. . . .

He served as . . . Deputy Campaign Manager of the Gore For President Campaign in 1988 and as traveling policy advisor on the Clinton-Gore Presidential Campaign.

I doubt anyone found Marshall Jr.'s career moves troubling. He was an adult and his decisions were his own, not the Supreme Court's. The same goes for the decisions of Alito's son.

Ornstein generously replied to my concerns on Twitter, suggesting that the Marshall Jr. example isn't comparable because it was a "different time," a "different Court," and a "completely different political atmosphere" back then. Putting aside whether that is the case—did working for Ted Kennedy on the Senate Judiciary Committee in the 1980s really put one outside the Court's business?—I'm not sure why any differences relate to the signal sent by the career decisions of a Justice's adult children.

Importantly, I'm not questioning the importance of the Justices themselves appearing—and, more importantly, being—non-partisan. But even so, I don't see how the career decisions of the Justices' adult children can fairly shed any light on the Court itself.