Since when is the cat not an observer?
Second, I'm not zen. Read my Buddhist Sunday School thread, I'm a Pure Lander.
We don't have "animalistic tendencies" we are above animals, who've once been animals, and remember our past lives as an animal. Somehow in a past life we did something good enough to get reborn a human, the first state in animal samsara(cycle of rebirth) which can reach enlightenment. Some who remember their animal life, think therefore that animal life was correct.
People become evil, and aren't born evil. Everyone can become a Buddha, it's the person, and their life experience which makes or breaks Buddhahood, based on past life karmic actions. Otherwise, how do some who grow up amongst thieves become police, yet some police become criminals?
You say evil doesn't exist. It sure does exist. Every action you do causing purposeful harm out of greed, ego, lust, ignorance, or hate puts that much more evil in the world. To claim otherwise is a sophist argument.
The whole, "forgive them father for they know not what they do." Sure you can forgive, that makes you better, but it doesn't excuse their evils. Only those who do evil can change their evil ways.
Your "argument" is, if I can convince myself it's not evil, then it's not evil is a wrong view.
It's like a feminist who hates Christians who hates gays, but goes to a rally to have Barabas the Muslim out of jail for cutting off his daughter's clitoris and then throwing her off a high rise building once he found out she was gay, because "Imperialist America intervened!"