I expect it's more like how people often inflect differently when reading from a script, or if they're self-conscious about public speaking in general.

I think it might be partially intentional too. Nigel always has this pristine footage with uniform white backgrounds. It’s almost clinical, and the inflection is kind of on theme with that.

In nileblue he doesn't talk like this. So clearly intentional.

Yeah I don't find it offputting, it makes sense for the presentation style. Although it's a bit jarring when you can feel like he's paused in the middle of a sentence to move to the next line.

That's why I cannot watch anime dubs. American voice actors are acting. Original seyuu often talk like normal people (there are exceptions of course, but in dubs it's 100% acting, they use "cartoon voice" which I hate).

I feel lucky that doesn't bother me when watching his videos.

I can sympathize with you somewhat though, because the Food Wishes channel drives me insane for a similar reason. (Chef John has mentioned he speaks that way for his videos on purpose)

Think Carmack is faking it too? Some people just have that cadence

I like his tone. For me as a non-native speaker, I never had any trouble understanding him.

You can definitely hear the difference in his more wacky NileBlue channel.

I enjoy the way he narrates his videos.

Once I noticed this I can't un-notice it anymore. It's not that it's robotic but that the inflections always follow the same pattern. There's an upswing and then a downswing with almost each and every phrase.