Precise wording aside, the essential content of the back-and-forth here is:
> When should one use Java on projects?
> One shouldn't consider Java because it lets you use null.
> That's easily solvable by just not using null.
> But you can't just do that. People will use it.
> You can just do that. Tell them not to.
Like I'm not seeing the issue. This is like saying you can't use Rust because people will use `unsafe` because it lets them do C programmer things, and then claiming it is simply impossible to tell them not to do that (and set tool policies to flag anyone attempting to).
In the real world, if you're in a position to even ask "why use Java for a new project?" then you are presumably also in a position to have "don't use nulls" be a satisfying answer to "what about nulls?" If someone is asked what technology to use for a project in the first place, they are almost certainly also asked about how it will be used. The hypothetical here is not "do you have coding standards" but "are you a decision maker," and when the original question is "when should one decide to do X," you have to accept as a premise that you are placing yourself in the role of a decision maker in the first place.