Yes, cocreation is a sham. Often enough, co-design is no better.
Cocreation is a buzzword that implies inclusive, user/community driven creation, but is code for getting input from potential participants during a construction process.
Have you ever heard cocreation used for something that's actually community driven? That's not called cocreation, because we already have words for it. It is called 'people doing stuff (together)'. We only call it 'cocreation' when we need to give it a process name that slots it into our top-down methodologies.
The typical story of cocreation goes something like this:
A. "Hey, let's build a cool thing!"
B. "Yes! But wait, that wouldn't be our thing, what you're talking about is a community thing, it needs to be community owned and driven."
A. "Oh, right, so we need to cocreate it?"
B. "That's brilliant, we should cocreate it and it's totally a community owned thing!"
It is probably better late than never, to admit I'm being polemic. 'Good' cocreation happens out there. And even 'bad' cocreation isn't malicious, normally.
But 'cocreating' isn't enough - it isn't simple, it isn't easy, and it can't be approached from the same top-down paradigm that most of us are used to.
Next time cocreation comes up, take a step back. Is the method being inserted into an otherwise top-down approach? (If you're not sure of the answer, it's yes. If you're sure the answer is no, but you can't provide a solid argument for it, the answer is still yes.)
You're probably best just admitting, and being aware, that you're the real drivers of your cocreation process.
If you actually want something to be owned and driven by the community, you're lucky enough to have come across a warning flag.
What to do next?
I don't know. That's the hard question.