I've limited martial arts experience, but I never look at faces for intent. I was looking at the body center like I've been trained and the position of the arms.
To me the arms/body position looked much more ready to block a punch rather than positioned for a powerful punch. And I kinda read Joe as a guy that if he is going to punch you, he's gonna make it hurt and put some power behind it. He's not going to throw a girly punch and I know with my arms in those places that's all I can throw.
I was taught the face should read ready for business whether you intend to strike first or just defend and only put the person down if forced to. And Joe wasn't in friendly mode, I think he was seeing if he could push Willie and see if the I'm not going to wait for the vote was a bluff or not.
Now I agree Joe was fed up with Willie and more than willing to poke at hornet's nest with a stick. I just didn't read the body posture as I'm intending to punch you out for daring to follow me after I said something to offend you. I read it as I'm going to block any shot you take and am capable, if needed, of putting you down if security doesn't get her fast enough.
But that's just how I read the posture and I don't think we got the whole story from the editing.