I've chased this paradox down the rabbit hole more than once, [...] Brooklyn Brewery on a PBS show. They were absolutely blowing their hot wort from their mash tun to their lauter tun with these huge pumps--it must've still been ~150F and just spraying every which way. I figured if THAT doesn't cause oxidation staling compounds then nothing does. And if the pros aren't sweating it, then I won't either.
I suspected as much. I wonder if the thing being spoken of is that same phenomena when many sorts of warm fluids are exposed to odd odors in the air and something in the fluid effects a strong bond with compounds in the air. This is an issue in dairy work especially home dairy work when milk is warm from the animal and is not chilled quickly. It can pick up odors in the air that can give it an off taste. Maybe in the home your wort might pick up the sulfur compounds in the air from cooking or a garbage pail nearby and take an off taste~?? Garlic and broccoli beer? I'm just guessing here but, I suspect that this is the case.
Compare to the vocational brewery where there is no garbage pail, no cooking odors it is all beer 24-7. Any odors picked up would be beer odors.
It's been my experience that on the internet an awful lot of information is passed around that may have some foundation in fact but yet is handed from person to person with no one asking any critical questions. And when the person passing the information on is generally knowledgeable (naybe even very much so) there is no reason to question every single thing he says.
This fellow tried to ask this exact question: "Must one aerate and what is the result if one does or does not?" So he conducted his own comparison tests.
http://brewery.org/brewery/library/WorAerJS.html
His result is that it makes no difference. At least it made no difference in the samples he ran and no difference that was observable on the gross level by casual inspection. He was not counting yeast cells.
I must confess I have never aerated. Never - ever. I just never gave it a thought. When I've seen people talking about doing it I thought to myself that it seemed to me that they were taking yet one more chance of contaminating their brew by sticking yet one more thing into it.
I sort of suspect that the yeasts need for oxygen can be met from surface interaction and residual oxygen in the wort even after the hour boil.
I have a twin stage Sergent Welsh rotary vain vacuum pump. And I have a vacuum bell. I think that sometime I shall hook the pump up to the jar with a volume of boiled wort inside and pull vacuum to see if there's any entrained gas in the fluid. I suspect I will find that it does give off gas - that boiling does not remove all the entrained air.
One could also do this with a hypodermic syringe just put some boiled wart in, plug the end with a finger, and pull on the plunger.
If bubbles result then that means there's gas in the wort.
I do not however, have a syringe.