Ugh. You don't trade away players because they're bad. You trade for players/assets you need. The Spurs trading Poeltl or any other player folks like isn't them punishing him or saying they prefer to keep Forbes or whatever. It's them saying that they really needed that return and the player was the best way to get it. It's possible that Jakob is the only player teams are willing to offer an okay first for. If the Spurs are rebuilding, then it doesn't matter that Poeltl is a serviceable young big. If they are still trying to make a run, it's only going to happen because LMA plays out of his mind. In either event, you can justify using him as part of the package. That doesn't mean that there aren't trades that wouldn't make sense or that PATFO wouldn't make a bad trade. But everyone on the roster is available for the right deal, not just ing Beli and Forbes and Carroll.
That said, I'm not a fan of trading for Russell, and he's the only possible target I've heard. I just don't think he's good enough. But I could see GS loving Poeltl enough to want him to be part of a Russell package, and that might give SA leverage to grab something of decent value from the team that actually acquires DAR like Covington, Culver, Winslow or Herro. If it's one the young wings, I could totally understand it, because the none of the young players is performing well enough to preclude the team acquiring someone at their position. I could see something like Poeltl and a top-10 protected first for Culver being a legit move to get top talent, and if it causes the team to fall apart and get their own top-10 pick, then the club could add much higher upside guys than just a solidly above-average but low-minute center.