@tanukihat : I am British, and the "h" in "history" has never been silent. Not to say I haven't witnessed people using "an" before it from time to time, but that was in spite of it NOT being silent, which just made it all the more jarring.
The letter "h" in general is suppressed in a lot of accents here, but that doesn't make it silent, and it tends to be a trait of.... what were formerly lower class accents... so it used to be looked down on. These days I'm pretty sure people just don't care.
Obviously the "h" in "herb" has never been silent here either, and I've no idea why the americans decided to try and make it so... or at least in the non-name term (since apparently even they can pronounce "herb" correctly if it is part of a name).
@tanukihat
i know this is an incredibly old comment, but forgive me because i've been holding this in for the whole series this far
it's just the artist's aesthetics. the characters are written much better than the plot, because the fact is that obligate carnivores die without eating animal protein (meat). egg does a pretty good job of replacing it, but it lacks the nutrients carnivores need. it's utter nonsense, but we put up with it for the willing suspension of disbelief, even if it's annoying