Peter states:

I think that the Fed is going to be doing everything it can to try to reelect Biden, or whoever may run if Biden does not. I think it's clear that that's what's going to happen." 

The President has the power to nominate the Federal Reserve chair, making this authority a crucial factor in shaping the Fed's decisions. As a result, the Fed chairman, in this case, Powell, is incentivized to align with the President.

This isn't necessarily a left-wing bias (although, Powell and the left-wing establishment enjoy a cozy relationship). The Fed chairman's alignment with the President transcends party lines:

It really doesn't matter the party affiliation of the Fed chairman… What matters is who is in the White House at the time. Because the Fed chairman always wants to play ball with whichever administration is in power."

That's just how the game works.

Outside administrations are okay with this, because the quid pro quo relationship benefits the new administrations as well.

Peter calls this the unwritten rule:

And I don't think outside administrations hold a grudge, because basically what happens is the Fed is going to try to help reelect whoever is in office. And so, if the opposing party wins, now the Fed is on their side. They're not really going to call them out or get mad at them for helping the past president when now they're the president and now the Fed has got their back. That's kind of the unwritten rule. The Fed always favors the incumbent. Now why? It's the incumbent that can renominate them."