We are not things. Intent matters.
Sometimes the most awful things are hidden behind bits of truth.
Because ultimately, behavior does matter. That's true.
But it's awful, because it pretends that we live in a world of philosophical zombies. Intent matters in relationships.
"If someone's kicking me, I want them to stop kicking me, not ask what their intent is."
(It's not a straw man argument if it's actually been said to you.)
Anyway, that's true; you want to stop problem behaviors, especially when people can lie about intent as a strategy to keep doing shitty things.
At the same time, your strategy is going to differ with someone who's kicking you because they like kicking people versus someone who is kicking you because they think you're an alien masquerading as their friend.
There's also a great deal of positive predictive power.
That person whose belief is simply "kicking people is fun"? They're gonna keep doing it. That person whose belief is that you're a pod person? As soon as you bleed regular blood, they're going to stop and apologize, and probably try to do better in the future.
But if intent doesn't matter to you, then you've responded exactly the same to a friend and a sociopath.
Which probably makes you a hell of a lot closer to the latter.