I'm with you. Not sure what they're taking about, I'm not conscious and I've never seen any evidence others are conscious.
How would you possibly behave the same without inner experience? There is a direct causal connection between inner experience and how one behaves. Your talking about inner experience just being one particularly obvious example.
You could in theory behave in exactly the same way without inner subjective experience. The argument goes like your brain gets exactly the same signals and processes them in exactly the same way, and initiates exactly the same actions, except you are not experiencing anything. Imagine a robot that gets sensory inputs from the world and processes them in some giant neural network brain and behaves very similarly to a human, and even claims that it is feeling things. Is it really feeling anything? So far we have absolutely no way of answering that question.
Not the same, but I can imagine a complex behavior patterns evolving, but without the living thing experiencing the same inner sensations. For example, psychopaths navigate the world and exhibit behaviors similar to typical people, but don't experience empathy or anxiety maybe. There are people who don't experience the same colors, or don't have an internal monologue. So maybe we can chip away at all other human experiences until behaviors are there, but void of any significant inner awareness, maybe just an internal model of the world, but without the qualitative sensation. Sort of like AI, a system of levers and pulleys that produces results, but isn't aware of it, like instincts on steroids.