Maybe he is a US Senator and doesnt want his identity shown?
Maybe he is a an Allied Fan Boy, but doesnt want to be seen talking about Axis?
Why not?
Or Maybe, he is talking about contravertial topic online and doesnt want that history to taint his future.
First, I skipped about, and saw nothing strikingly controversial. Second, I think I have a pretty good guess in what way it's supposed to be "controversial" and something he might be "tainted" by.
Third, and most importantly, that isn't how science, and academia more generally, works. It's the controversial topics that garner the most attention, that will get you a Nobel prize. And seeing as nobody gets burned at the stake any more for heresy, it's also perfectly doable.
So this hiding identity stuff is all bogus; there;s no credible reason for it. And so what we are left with is figuring out which non-credible reason might be operating.
And I suspect we can all make a pretty good go of that, can't we? Indeed, suggesting he might worry that this history will 'taint' his future sort of gives it away, doesn't it? At the very least, it;s very suggestive.
There are many reasons why people cover their identity. Listen to what is said, not the method of delivery.
But not all of them are GOOD reasons.