I have to ask, what kind of deed does a vampire have to do to reach Humanity 1 or even 0?
It's not that hard to imagine it, actually. In short, anything your average serial killer would be up to.
The way you read that table is "what's the smallest thing a vampire would feel remorse for, depending on their humanity?". Passing a Humanity check means your character actually
felt that remorse and held on to their moral compass. So a Humanity 10 Vampire would feel remorse for even selfish thoughts, while a Humanity 3 vampire wouldn't necessarily bat an eyelash at accidentally running someone over with their car. They'd more likely get annoyed at the cost of removing the dent on the hood. Note that "feeling bad about it" and "doing something about it" are not necessarily the same thing. So a Humanity 5 vampire running over someone might just go
"holy shit, I ran someone over!", and just... keep on driving just because they're jerk. Or being chased by a pack of angry Glass Walkers. But statistically, the more you flaunt the odds, the more likely you are to slide down the scale. Eventually, the
"holy shit, I ran someone over!" turns into a simple
"aw, fuck. She cracked the windshield with her head!" and there goes your Humanity.
"Utter perversion or heinous acts" is kind of left to the ST's taste there, as essentially the final "even I have standards" barrier for a character. Torture, rape, cannibalism, child molestation, murder: pick two or more and add "with gleeful intent" to the end. Anything that would get people thinking "how could anyone do this?" if they saw it on the news. Humans that do these things are
seen as irredeemable monsters. Vampires that do those things
become irredeemable monsters as their inner Beast takes over.
(Note that Humanity also has certain rules interactions, like how long a heavily injured vampire stays in torpor for, or how difficult it is to wake up in the
morning evening.)