They would need change their model to meat based burgers after they gain market share for their mission to be BS. Profit has nothing to do with it.
What you are proposing would prevent them from building a healthy company that can maximize market share and have the largest possible beneficial impact on the environment. I want them to drive all the meat based competitors out of business.
Maybe open source IP model would fail to get critical mass. Maybe the best path forward is to get Burger King as an investor.
If they maximize profits while still being committed to an environmentaly friendly meat replacement, that doesn’t mean they are limiting their impact in any way. It’s just as likely they are maximizing their impact.
I personally don’t care how much money they make, but I do care about the environment and animal rights.
While doing that they have some additional missions, which is cool, but in absence of that first point I do agree it comes off as marketing BS.
[0]: https://en.wikipedia.org/wiki/Impossible_Foods#Financing
If not, the purpose is to make money and the "mission" is just marketing BS.