I'm going to go out on a limb and say the committee didn't pursue the questioning further because had he been a fed or plant, the narrative gets really fucked for them because the right would run with he's a fed from the left. It makes no sense to me this was the job of the left because they held the house, senate, and presidency. So why do it? I mean you never know, but it makes no sense to me still. All the other stuff on Trump doesn't distance himself from the alt-right is true, but pursuing it maybe means changing that narrative.