You’ve got to feel for this guy. He spends hours installing a new cat door for his feline friend, only for her to metaphorically stick two fingers up at his efforts.
The cat is not going to play ball by simply walking through the new cat door. No, no, and thrice no. That is too simple by far.
Instead, she’ll do what she has always done when faced with a closed door: turn the handle and casually stroll in like a human.
The lesson here is to not try to tell cats what to do. They simply won’t have it. They’re independent creatures which only stick around because you feed them. Otherwise they’d be off round the neighbor’s house.