Windjammer's entirely correct -- if we want to go down this route that only practical way of preventing political activity by Justices would be an outright ban on just that. Such would, of course, be extremely difficult to enforce. But a ban on officially holding an office would, if anything, only serve to push political activity behind the scenes and into the shadows, making the problem it purports to solve worse.
This is indeed problematic and one that ironically myself and others pointed out in 2016. The very types that would indeed be engaging in wrong doing, would be the ones this is completely toothless to do anything about.
