and it's likely that they won't or can't
Oh. They can. Like all things in life, it is what one prioritizes.
Most people specialize in being ignorant, misinterpretation, and being over sensitive.
The point about transparency is also questionable because several of them do provide certification
AV lab certification does not mean anything unless a person blindly trusts certification as meaning something.
How can anyone trust an organization that is not transparent?
Who, in their right mind, would trust black box testing that is done on behalf of the paying client to generate marketing tools from the test results for the client?
It is proven that audited companies and governments very often are untrustworthy despite passing many audits. AV labs are no different and there's no good reason why anyone would think that any one of them being certified, that they behave and do things in a manner that is blindly trustable and their work product should be accepted as fact.
show videos of what they did.
What is proven by a video? So, OK, the Youtube Tester executes some malware samples. How does anyone know that every single one of those samples is actually malware? How does anyone actually know that, if indeed a malicious file, does what it is supposed to do and that the AV completely blocked it? How does anyone know if the file, when executed, just loads into memory, consumes a little bit of resources, but then actually does nothing? How does anyone know from what is being shown in open Task Manager or similar what is really happening on the system? How does anyone know that the "end of test" tools are detecting everything that was missed by the tested AV? How does anyone know that everything used to perform and "confirm" the test results is identifying all false positives?
If the tester does not provide the samples or the files used, then one should question the results outright. It's the common sense thing to do.
Now, notice, I did not say "Dismiss outright." What I said is "Question the results." Those are not the same thing. Because you have a habit of reading what a person posts and then having your own unique, peculiar interpretation that is different - and probably deliberately so - from what the poster meant or intended.
The point about their having to admit that they're wrong is also questionable
I never said anyone needed to do anything. They can decide what to do and not to do.
How does anyone not expect them to admit they're wrong, when they make mistakes are wrong (which happens in both professional and enthusiast testing routinely)?
How does anyone trust them when they are wrong, but they don't admit it?
what if they're not wrong?
Then they don't have to admit they're wrong. They should if they want the public's trust, but they don't have to.
They are making claims about products. So the accountability and responsibility to prove their claims is entirely on them. Making false claims or misleading consumers - whether by intent or not, and then not admitting they were wrong or misleading means nobody should trust them.
Then do you admit that they're right?
For the most part they are right for the specific malware samples, the specific methodology, and the specific testing circumstances of the test(s).
It is people who misinterpret the results by extrapolating the results to any possible real world circumstances. And those people do so without thought.
But when a tester is wrong, they should be transparent about it and admit that they were wrong.
Your last point implies that no one should be trusted, not even those who present tests here, because they're either not revealing their mistakes or they're making mistakes.
Because they can and often do, and they don't even realize that they're making mistakes. This is well known and widely accepted as fact.
"Trust, but Verify."
How can anyone confirm and verify professional test lab methodology, samples, and results, let alone video testers? Just blindly trust them and curl the toes with glee because one's favorite AV got "5 Stars and All Green Bars?"
Given that, what then is the basis of making a choice on what to purchase?
Gain adequate knowledge to confirm for oneself. Know how to spot problems and identify BS. Be skeptical because it will save one's bacon from being cooked needlessly and money, if they be a paying consumer instead of a software pirater or freeloader.
You seem very willing to trust marketing claims - that are often highly problematic, up to the point of being misleading. As far as Youtube Testers, anyone that keeps posting test videos with positive outcomes and bypass videos with negative outcomes has an agenda. Anybody that conducts an international campaign of live demonstrations to show how their product is superior to every other product has an agenda.
Anyone that keeps promoting their product or a product through participation on a forum has an agenda.
The agenda is always to influence the viewer one way or the other. And that means huge bias. Which means the viewer should be skeptical, unless they be the ignorant, gullible type.