This Humanity scale makes it seem as if your average young vampire would be somewhere around Humanity 4 or 3. What kind of lunatic has Humanity 10 as a vampire?
As
@Adamska said, most neonates start around 7. It depends on who they were in life, of course. A handsome and pious clergyman tricked, seduced and embraced by a Toreador would start higher, while a ruthless thug who's served time for multiple murders embraced by a Brujah would start
way lower. In game terms, initial Humanity is defined by your Conscience + Self Control, while initial Willpower is defined by your Courage. You start with 7 points to distribute between Conscience, Self Control and Courage, and you can spend bonus points to increase them during chargen.
Anyway, a lot of
mortals wouldn't have Humanity 7 to begin with, but 7 is picked as the average simply because
most people think stealing is wrong but don't get
too hung up on injuring other people (a good apology is enough). Once Embraced, vamps tend to go through a power trip period while they're experimenting with their new condition and realizing how much more powerful they are than your average mortal. Even a freshly-risen neonate can tank a stab to the gut that would kill a normal person, for example. That power trip often results in their humanity taking a couple of dings, which may or may not be recovered later as the vampire's psyche stabilizes and a lot of them sort of renounce their "youthful foolishness". So yes, most vampires of reasonable age would be between Humanity 4 and 6. At Humanity 3 the vampire starts getting a bit too uncanny for most people. The ones that hold on to 7 or higher after a century tend to be exceedingly principled people. And often very shrewd in order to avoid being manipulated by others.
Humanity 10 is
absurdly rare. On the other hand, if you look at the table you'll see that
feeding doesn't cause any issues, only feeding too much or killing people while feeding. So, if you somehow managed to retain a "normal", mortal-like life after becoming a vampire and didn't get into a lot of trouble, you could probably stick to Humanity 7 simply by doing the old standard of going to a nightclub once or twice a week and seducing someone for 3-4 points of vitae a pop and suffer no moral quandaries. Or you could use that wonderful Background, Herd, and have yourself a small group of blood dolls that willingly give you blood on the regular.
One of the coolest NPCs I saw in the chronicles I played was a nun on the path to Golconda. She was old as balls (and accordingly powerful), and was the one responsble for building the convent she used as her haven, a few centuries back. The ST didn't reveal what her Humanity was, but it was probably 9 or even 10. Her Herd were the sisters in that convent, who opened their veins into a stone basin for the vampire to drink so they could avoid the "vice" that was the pleasure provided by the Kiss.
(We had to retrieve an item in that convent without the vampire noticing it, it was fun couple of sessions distracting the nuns and sneaking about.)
Anyway, it is
possible to retain high Humanity as a vampire, but it requires you to be both extremely virtuous... and an outcast in vampiric society. Seriously. Don't talk to other vamps. Find yourself a nice secluded place with understanding mortals. Playing the political game at all is guaranteed to drop you back down to
at most Humanity 7 in very short order.