A lot of bluffing going on….

The commentators are wrong. Here’s a quote from the youtube comments:

These commentators have no idea what is going on.

Murphy is not calling twice with A high because he thinks his hand is good, he’s calling to represent a 2 and steal the pot on the river.
Because he knows John Juanda almost never has a 2 as a pre flop raiser and Murphy could defend his blind with A2. Also he’s first to act on the river and he knows Juanda is not committed on this street.
If you are Juanda there and you have AQ or even kings, you can’t make the call for all your chips