Well he started PF with a squeeze attempt on 2 guys he thought were probably on the weak side. He figured the only reason Newhouse got in was because he was thinking Larrabe was up to something. So it was a good opportunity to run a squeeze, and that is hardly ever about what cards you are holding (or shouldn't be).
I'm sure he was less that thrilled with the Newhouse call, but then he gets a great flop hitting the 7 and also figuring with some certainty that Newhouse isn't in this hand with a 9, let alone a 3. Now he's thinking he has a good chance at being ahead of KJ-AK. No reason to slow down. Another great card for him on the flop - again he is certain Newhouse is not in the hand with a 4 based on his preflop action. And as Chad explains, the Newhouse bet makes no sense to his action line. The only thing that makes sense is for this river bet is trips when the 3 hit one the river - BUT if that were true then Newhouse's preflop action makes zero sense. It would be correct to call with that board as none of Newhouse's action showed him hitting any part of it - no 9, no 7, no 3 and no 4. The only thing it could be is an overpair and chances of that were remote.
Politano made a bold preflop move, got caught and then got cards.
Newhouse made a pretty transparent bluff and got called.